Backford

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This map shows the sea level raised 15meters shows the "Backford Gap" quite clearly. It can also be seen how Ince is an island. Inis is the old Irish, Manx word for "island". Burton Point protrudes into the estuary at the top left.

Samuel Lewis, in his "A Topographical Dictionary of England" (1831) describes it as follows:

  • "BACKFORD, a parish comprising the townships of Backford, Chorlton, Lea, and Great Mollington, in the higher division of the hundred of WIRRALL, and the township of Conghall, in the lower division of the hundred of BROXTON, county palatine of CHESTER, and containing 450 inhabitants, of which number, 140 are, in the township of Backford, 4 miles (N.) from Chester. The living is a discharged vicarage, in the archdeaconry and diocese of Chester, rated in the king's books at £5. 0. 5., endowed with £400 private benefaction, an £400 royal bounty, and in the patronage of the Bishop of Chester. The church is dedicated to St. Oswald. The Ellesmere canal passes along the southern side of the parish."

He adds :

  • "CONGHALL, or COUGHALL, a township in that part of the parish of BACKFORD which is in the lower division of the hundred of BROXTON, county palatine of CHESTER, 3½ miles (N. by E.) from Chester, containing 23 inhabitants. The Ellesmere canal passes near this place"

Backford's page on Wikipedia is very short and Caughall gets even less of a page. However, a notable topographical feature of Backford is the so-called "Backford Gap", from which the "ford" part of the name probably arises. This valley provides a route for the Chester Canal to cross the neck of the Wirral with locks only needed at the ends. The Wirral Line, as it is known, was completed in 1795.

In the past the valley has been involved in considerable debate as regards its hydrology and origins. The depth of the gap is best appreciated at the railway bridge over the canal. This bridge dated 1839, is by George Stephenson and John Dixon for the Chester and Birkenhead Railway Co. It is constructed in rock-faced red sandstone with blue and orange brick vaulting. The bridge is sometimes known as Mollington Bridge as the now-disused Mollington Station was just to the north.

Mapping Confusion

Early maps and descriptions give a seemingly improbable course for the Gowy, with the river splitting in two at least twice and branches emptying into the River Dee via Aldford Brook and Backford Gap. Ormerod cites a very peculiar version of the course of the Gowy (taken from Hollinshed), with it actually dividing the Wirral from the rest of Cheshire by flowing into both the Dee (as Flookersbrook) and into the Mersey:

  • "That, therefore, which they call the Gowy, hath his head not far from Bunbury, and runneth north-west by Beeston Castle, to Teerton and Huxley, where it divideth itself into two parts ; one goeth west to Tattenhall, Gosburn, Lea Hall, and at Aldford falleth into the Dee. The other part goeth northwards to Stapleford, Hocknel-plat, and Barrow (where it taketh in a brook that Cometh from Tarporley and Tarvin), and so passeth to Plemstow-bridge, Trafford, Picton, and Thornton, where it divideth itself again into two parts; one of which keepeth its course north-west to Stanley, Stanney, and Poole, and afterwards falleth into the Marsey. The other part goeth south-west to Stoke, Croughton, Chorlton, the Baits, and so falleth into the Dee, hard by Chester, being there called Flooker's-brook, and divideth Wirral from the rest of Cheshire; and therefore some imagine that it is called Wirral."

This supposed course of the river is used to define parts of the bounary of the Broxton Hundred. However, it may well be that significant parts of the river were diverted at various times and in various places, particularly to power water-mills, or to prevent or reduce flooding. Even today, the boundaries are often the old ones and do not always follow the mid-line of the river. However diversion of the river was never on the scale that Hollinshed implies. Why Hollinshead should get it so wrong is a mystery. Ormerod had the advantage that he lived at nearby Chorlton Hall in Backford while writing his "History of Cheshire" and would have been familar with the local hydrology.

Robert Morden's map from William Camden's Britannia (1695) shows the Gowy rising near Peckforton, but then splitting near Huxley to flow over to Aldford and become Aldford Brook (which is quite wrong) and then splitting again at Thornton to flow both into the Dee and the Mersey, which is again quite wrong unless this was the course of the somewhat mysterious "River Twine". There was originaly a stream along part of this route which is now taken by a section of the Chester-Ellesmere Port canal. This is a "colourised" version of the map, for which the original can be found here.

Ormerod never studied the area around Stanney and Thornton in any detail. He is known to have had a low opinion of the area around the lower reaches of the Gowy. He describes this area as particularly gloomy with Stoak being: "..a collection of of rugged and filthy hovels scattered around the church..", and Picton being "situated in a cold flat, clayey soil; in roads appearance and in inhabitants it may be safely said to present a complete picture of barbarism..". Ormerod saves his strongest words for Stanlow and says: "It is difficult to select a scene of more comfortless desolation than this cheerless marsh .... approached by one miserable trackway of mud".

A 1608 map showing Golborne brook connecting the Gowy and the Dee, and a second branch connecting the two rivers and passing Ormerod's home near "Blakeford".

As noted above Morden's 1695 map shows a peculiar splitting of the Gowy in two places. The error occurs in the map of Christopher Saxton (c. 1540 – c. 1610) from 1577. This same feature was repeated in many later maps of Cheshire. The fact that the border between the Broxton Hundred and the Wirral followed the track of the supposed watercourse may have helped support a misconception that there was a significant topological feature - such as a river - along its entire length. To be fair, the Wirral Line of the Chester Canal had been completed in 1797 and may well have obliterated some of the signs of the earlier topography by the time that Ormerod was writing (1811 to 1823). Lysons in his Magna Britannia appears to get it right and describes:

  • "the stream called by Leland the Wyrall which ryseth within less than a quarter of a myle of Chester and falleth into Dee at Flockersbrooke without the north gate wherein is a docke called Port Pole for great ships to ryde at spring tyde"

It is possible that the Gowy did split if only in a hydrological sense, in both locations described by Ormerod. Golborne Brook roughly follows the southern branch of the Gowy and nowadays carries very little water. However, there has been considerable extraction of water from the sandstone in the Peckforton area which has much reduced the flow of both the Gowy and other watercourses in the area. The significant changes in the local hydrology are evident from the fact that there were several noted springs in the area which are now almost dry including a "spa" at Beeston. The Golborne was a significant feature at the time of the Civil War with Golborne Bridge being an important ambush location. The bridge itself at Golborne is a substantial structure provided with a cutwater and a separate arch for flood water. While there may have been no surface flow from the Gowy into the Golborne there are many buried, post-glacial gravel beds in the area which could have allowed some, perhaps even significant, flow between the two watercourses after heavy rain.

Hollinshed's mapping confusion about the Wirral was not the first, as there is an earlier one going back to Roman times.

Ptolemy's Map

Claudius Ptolemaeus, better known as Ptolemy, (c.100 – c.170) was most likely a Roman citizen, probably of Macedonian descent, who lived and worked in or around Alexandria, Egypt. He was a celebrated geographer and astrologer who lived in the second century A.D. He wrote all his scientific works in Greek but, his work, like so many ancient others (especially those in the Library at Alexandria), was lost for over a thousand years to Western scholarship. It was not until the later Middle Ages that his work was rediscovered and translated into Latin.

At the time that Ptolemy was writing Roman Chester had already been established and indeed Legio XX had already moved here replacing Legio II. The Romans would have been familiar with the geography of the Irish Sea given the campaigns of Agricola in the years 78-84 (see: Roman Ireland), when Chester was used as a base for supply by ship along the Irish Sea coast. In 122AD construction of Hadrian's Wall started and the Legio XX (or at least large parts of it) moved north. During the following years not only did building work at Chester almost cease, but significant areas within the Roman fortress were abandonned to the point of dereliction, stones were stripped from pavements for re-use and some area's even used as rubbish-tips. The extent to which Chester was an active port during the lifetime of Ptolemy is not well understood, but from the barracks which had not fallen into disuse during this period it is possible to estimate that a small part of the XXth Legion remained in Chester. At this time the fortress at Chester was probably used as a storage and supply station. Changes in the character of occupation after c. 130 may be explained by an intention, perhaps implied in an incomplete inscription found reused behind the headquarters, to demilitarize the site and establish an independent civilian settlement. In 163 the order is given to abandon the Antonine Wall and for Roman troops to withdraw to Hadrian's Wall. Although the reasons are unclear, it is probable an uprising by the Brigantes forced the retreat. Chester would only become a thriving Roman military base again well after Ptolemy's death.

One version of the Ptolemy map for the Irish Sea coast. The Roman name Moriancabris Æsturis was first identified in 1771 by John Whitaker as what is now known as Morecambe Bay. It next appears four years later in Antiquities of Furness, where the bay is described as "the Bay of Morecambe". Before this is was simply "the sands".

Ptolemy is often said to have produced a map of Britain. That is not quite true: in Chapter 2 of his "Geography" he gave lists of the prominent coastal landmarks, river mouths and estuaries, as well as the names of the British tribes and their principal towns. This data included latitudes and longitudes, so it is possible to plot a map using it by placing the dots on a grid and joining the "coastal" ones. When the data are plotted, an obvious error becomes readily apparent: everything north of the Solway Firth (Ituna Aestuarium) on the western side and the mouth of the River Wear (Vedra Fluvius) on the eastern side appear to have been rotated clockwise by 90°, so all directions north of Hadrian’s Wall should be adjusted accordingly. This may well be an error introduced as "Geography" was coppied down the centuries. A further problem with Ptolemy is that he appears to have allowed the same number of miles to a degree of longitude through all of Britain, whereas in reality as one moves northward lines of longitude converge.

The stretch of "Roman" coastline from Caernafon to Cumberland has been the subject of quite some discussion. One version of a map created from the tables provided by Ptolemy is reproduced to the left. There are problems with identifying the features in the map, which are mostly estuaries, with modern counterparts. Ptolemy does not provide any descriptive information other than the location of a feature, and there has been a tendency amongst map-makers to fill-in detail with modern knowledge. In the map to the left, for example, the shape of "the Wirral" as depicted may have been influenced by later knowledge. William Camden makes the Belisama the Ribble, or, as he would write it, the "Rhe-bell". John Horsley says the Belisama, "from its situation, must be the Mersey": both of these interpretations have been criticised. Ormerod concludes that the Belisama is the Ribble and bases this on an interpretation by Thomas Dunham Whitaker which uses "corrected" longitude of the Belisama estuary to "prove" it is the Ribble and not the Mersey.

Roman Liverpool

Roman Liverpool is something of a mystery as there is a surprisingly small list of Roman archaeology. The most significant finds in the region include the Burscough Roman Fort a c.1st century AD auxiliary fort near what is now Burscough, West Lancashire. This has received official recognition from Historic England, but its dating is uncertain. The settlement and administration of west Lancashire during the Roman period is in general poorly understood, and the recently discovered Roman fort and sections of Roman roads at Burscough potentially fills a large gap in knowledge of the military occupation of lowland north-west England. It is possible that the site was referenced in the diaries of Nicholas Blundell on 28 September 1721, when he noted "a place in Francis Farrer's ground" where "tis supposed there formerly stood a small Castle". The site was identified in a Tithe map of 1846 as "Castle Field", likely with reference to its history as a former Roman fort.

The conventional view is that the Roman's initially confined their operations to the south of England and only expanded northwards in the period 44-60 with the new governor of Britain, Publius Ostorius Scapula, began a campaign against the tribes of modern-day Wales, and the Cheshire Gap in 47 under the Emperor Claudius (41-54). Roman Chester (as Deva) was established sometime around 73 CE when the then governor of Roman Britain, Sextus Julius Frontinus constructed an auxiliary fort on the River Dee.

Other Roman sites in the region included one at Warrington, which was largely a manufacturing site. The Roman name for the settlement is not known but there is speculation that it could have been Veratinum which is listed as a Roman habitation in the area during the occupation period. However, others have proposed a new settlement was established on the site of Warrington by the Saxon "Wærings" who could have equally well given the place its name.

William Ashton

William Ashton's map of the supposed extent of the "Mersey Lake" in Roman times. In reality, the mouth of the Mersey was probably blocked by the Irish Sea ice, but at a very much earlier period than Roman times.

One consequence of these varying interpretations was that it was believed by some that the mouth of the Mersey was not shown on these Roman maps. As a consequence of that some once believed that the Mersey flowed through the "Deva Spillway/Backford Gap" (also called the "Broxton Valley") to enter the Dee estuary between Blacon and Chester (as Flookersbrook) in Roman times. One proponent of this was geographer William Ashton around 1909. This was based on supposed evidence and local traditions;

  • the "fact" that the Mersey was not marked on Ptolemy's map of the world;
  • assertions that a Roman bridge at Wallasey Pool was found below the current sea level;
  • evidence for major flooding in parts of Cheshire around the 6th century; and,
  • evidence of silts and clay in the Backford Gap (aka "Broxton Valley").

The "local traditions" to which Ashton refers are mentioned in William William Mortimer's "History of the Wirral" (1847, see page 141ff). Ashton quotes Mortimer as stating:

  • "traditions have for ages existed that the two counties, Lancashire and Cheshire, were at one period connected until rent asunder by some violent convulsion which is believed to have occurred in the tremendous earthquake and inundation which visited the west of Britain in the 5th century."

This is not actually a direct quote from Mortimer, who goes on to add that the confirmation is in the form of fossil remains "with which these parts abound, many of them animals unknown in these days". Mortimer actually attributes the theory that the mouth of the Mersey was recent to Joseph Brook Yeats founder of the Liverpool Literary and Philosophical Society, of which he was president during four triennial periods. He was the author of a "Memoir on the Rapid and Extensive Changes which have taken place at the Entrance to the River Mersey", 1840; he brought the same subject before the British Association in 1854, when a committee was appointed to investigate the matter. An elaborate report was printed in the British Association Report, 1856. Yeats' original memoir is presented as an appendix in Mortimer.

None of these dates take the record back before Ormerod who was writing c.1815, but there is one interesting clue to a possible earlier source. This is found in the chart of the mouth of the River Dee as prepared by mathematician and surveyor John Mackay in opposition to "A Bill to Recover and Preserve the Navigation of the River Dee, in the County Palatine of Chester, 11 June 1732". The chart was commissioned by the London Cheesemongers, to accompany The "Case of the Cheesemongers, in and about the Cities of London and Westminster, relating to the Bill to recover and preserve the Navigation of the River Dee, in the County of Chester"; the Cheesemongers conducted their trade through the port of Parkgate on the northerly side of the Dee estuary, and they feared their route would become silted up by the proposed new works to "canalise" the Dee (see: Cheshire Cheese).

Mackay's map (c.1730) shows a watercourse from Chester to "Poole".

Almost nothing is known about John Mackay beyond the small number of surveys that he completed; he was a mathematician and surveyor, with a father of the same name and profession, with whom he surveyed the Parish of St. George's Hanover Square in 1725, both describing themselves as of the Parish of St. James's Westminster. Mackay's map (found: here) appears moderately accurate although it can only be compared with later maps of the ever-shifting sands in the River Dee. The eastern edge of the map appears to show a watercourse running from "Poole" on the Mersey to Chester. This follows roughly the line of the later canal from Chester to Netherpool and the "traditional" Mersey/Dee connextion. It is likely that Mackay never visited the Backford area and simply copied the older and erroneous maps. His mapping on land is also a little suspect as he shows three windmills at Chester for which no evidence exists. There is a dividing line laid across the Wirral with the note "All on the East Side of this Line is laid down from a Draught of the River Mersey". Whether that was a draft by Mackay or some other is unknown.

William Ashton concludes:

  • "There is little room for doubt that in the time of the Roman occupation that part of Liverpool Bay inland of a line connecting Formby Point and Hilbre Island, at the entrance to the Dee, was dry, or marshy land, and, not improbably, inhabited. A point which is more open to question is as to whether any direct connection had at this time been formed between the sea and the extensive inland lake which, within the period of the Christian era, occupied the area of the broad upper end of the Mersey estuary between Garston, Runcorn, and Ellesmere port."

William Ashton's map is reproduced on the right and shows his theory of what the local coastline looked like in the second century. The modern mouth of the Mersey does not exist, but the Mersey estuary is blocked forming a large inland lake. The river Birket flows into this from Great Meols and the lake empties down the Backford gap into the River Dee at Chester. A consequence of this, which Ashton does not explore, is that it would probably have been possible to sail up the Backford Gap to the "Mersey Lake".

Ashton's theory was criticised at the time. Rideout (1922) wrote:

  • "Unfortunately for this theory, a little closer inspection of the valley between Wervin and Chorlton will reveal the presence of a prominent watershed approximately 40 feet above sea level. Further inspection will show traces of the former presence of two streams; the one rising within Wervin township and flowing north-east to join the Gowy and eventually the Mersey, and the other, a few yards below this, flowing south-west and joining Backford Brook. Regarding the marine shells, possibly those seen by Ormerod were those from the glacial clay which competent geologists state were brought in, together with the clay, by ice action in the glacial period. The sands are probably also the middle glacial sands of frequent occurrence in the neighbourhood. Ormerod certainly withdrew his earliest statements, but writers since that date have apparently neither seen this withdrawal nor taken the trouble to inspect the spot in question".

To be fair to Ashton the "watershed" mentioned by Rideout is not that prominent. The Wirral line canal has no locks save at the ends and there is no sign of any kind of cutting needed to pass a watershed. However, Ashton's theory is (according to Stephen Roberts, A History of Wirral, 2002), not generally accepted now. Research in the 1970s by Ray Kenna and others concluded that:

  • "There is no evidence for the Mersey flowing into the Dee through the Broxton Valley in historic times or during the last 10,000 years"

The Backford Gap, it is now thought, was formed during the ice age when the Mersey entrance was blocked, either by a glacial moraine or by ice itself, and melt waters flowed into the River Dee. The precise course taken by the waters onwards around Chester is not certain, but it is possible that they flowed "upstream" through Chester and helped to create the "Chester Gorge" between the City and Handbridge.

It is possible, but by no means proven that the Backford Gap did not discharge into the Dee estuary near Blacon Point but that the melt-water ran "up-stream" through Chester cutting out the Chester Gorge and finally reached the estuary at some other point. Eventually the flow eroded its way through the high ground between Handbridge and Blacon Point.

Legends of Floods

Ashton's disproved theory can be traced back through Mortimer (1847) to Yeats (1840), but it is possible to go further. Yeats suggests that the theory might have been older still and quotes Pennant's recordal of a Wirral saying "From Blacon Point to Hilbree, The squirrel might leap from tree to tree" and cites several other references to vanished coastal woodland and shells having been found in the Backford Gap. He appears to further suggest that the theory originated with a Captain Denham. This is Henry Mangles Denham (28 August 1800 – 3 July 1887), who in 1833 was assigned to survey the mouth of the Mersey.

However Denham was not alone, the following is found in a Report of Messrs Telford, Stevenson and Nimmo on the Rivers and Mersey in May 1828:

  • "In the time of the Romans the Ribble seems to have been the chief port of this district and Ribchester (Rigodunum) is said to have been a city as great as any out of Rome; the port was Poulton below Preston at the Neb of the Naze so vastly inferior at the present time to various situations on the Mersey and the Dee that it is impossible not to admit that some extraordinary change has taken place in their physical condition since that period. Tradition says that the port of the Ribble was destroyed by an earthquake and also that there were tremendous inundations in Cheshire and Lancashire about the termination of the Roman dominion in Britain. Various phenomena we have seen point to some such catastrophe."

This report and others were discussed at some length by Hulme in paper on "CHANGES IN THE SEA COAST OF LANCASHIRE AND CHESHIRE". The sea level has certainly changed due to several factors, including the release of water from ice caps, thermal expansion of water as the climate changed and post-glacial rebound of ground after the removal of the ice overburden. However, Ribchester is not Rigodunum, which is now believed to be the Castleshaw Roman Fort in the Pennines, on the Chester to York Roman road. Ribchester was the Roman Bremetennacum and there is no evidence that it was destroyed by an earthquake.

The statement that "tradition" actually records an earthquake which caused major changes has proved difficult to verify, but a reference does appear in Camden:

  • "Since Ribchester, in length of time was ruined by war, or, as the common people think, by an earthquake, lower down where the Ri-bill receives the tide, and is called by the geographer, BELLISAMA ESTVARIUM, near Penwortham, where, in the conqueror's time, was a castle, as appears from that prince's survey, out of the ruins of Ribchester arose Preston, a large and, for these parts, handsome and populous towne... "

There is a local saying in Lancashire that: "It is written on a wall in Rome that Ribchester was as rich as any town in Christendom", this is hardly justified by the archaeology and one can only speculate where the saying comes from. Geographically these discussions are very loose. We have a report by Camden that Ribchester a small cavalry fort was (traditionally) destroyed by an earthquake and rose again (12 miles away) as Preston. None of this has anything to do with the Mersey.

There are other legends of flooding which have been dragged into the tale. The name "Setantii" is known from a single source only: the 2nd century Geographia of Ptolemy. Recorded there is the placename "Portus Setantiorum" (Port of the Setantii). Its precise location remains unknown although various suggestions have been made, including the possibility that it has since been lost to the sea. An alternative explanation is that it was a place known to the Romans as a suitable anchorage in case of poor weather. Sir John Rhys (21 June 1840 – 17 December 1915) linked the name of the Setantii with Seithenyn, a figure in Welsh mythology. Seithenyn was a prince with responsibilities over the sea defences of Cantre'r Gwaelod. Drunkenly neglecting his duties one night, the sea overran the kingdom, and it sank beneath Cardigan Bay. Rhys noted the similarities between Setantii, Seithenyn, the Irish Sétanta Beg, and the Breton legends surrounding "Enez-Sizun" and the Lost City of Ys. Rhys posited that, although the name was Brythonic in origin, the soundings of the later legends "left no doubt" that "we have in these names distant echoes of an inundation story, once widely current in both Britains (Great Britain and Brittany) and perhaps also in Ireland". Although he acknowledged he was unaware of any similar legend on the Lancashire coast (such as the inundation of Portus Setantiorum), Rhys linked all the later legends back to the Setantii of Lancashire.

Such inundation legends are common: even the River Dee has a similar inundation legend. The Dee legend is that near to what is now Bala Lake was a walled spring that had to be secured and locked every night with a lid so that the spring water would not be corrupted by supernatural influences. For whatever reason (one reason given is drink), the man responsible for this task neglected his duty, the water burst forth from the spring and completely drowned a nearby town, and this is how Bala Lake was formed. Real floods are also known from history: the abbey at Stanlow was in an exposed situation where the Gowy emptied into the Mersey estuary and it suffered from a series of disasters. According to the Chester Chronicle, there were serious floods in 1279 at Stanlow then in 1287 a violent storm destroyed the the church tower. Two years later a fire destroyed much of the abbey and a second inundation flooded it to the depth of three feet. The monks appealed to the pope for the monastery to be moved to a better site and, with the consent of pope Nicholas IV and the agreement of Edward I and Henry de Lacy, the 10th Baron, they moved to Whalley Abbey near Clitheroe, Lancashire. This new site was well above sea level (but prone to flooding from the Calder).

LIDAR image of the region clearly shows the Backford Gap. Ormerod notes that the Dee and the Gowy are separated by a ridge extending down the Wirral and that the Backford Gap, which forms the boundary of the Broxton Hundred is an interesting feature.

Another source which Ashton appears to use is Joseph Boult of the Literary & Philosophical Society of Liverpool. Boult was an architect and antiquarian. Writing in 1873 Boult tries to portray Ormerod as favouring the theory of a connextion between the Dee and the Mersey. He uses this to support a very dubious theory that the name "Seteia" (which he believes to be Ptolemy's name for the Dee) means the estuary of two rivers. In effect supporting the view that the Mersey flowed into the Dee in Roman times. His interpretations of place names then becomes quite outlandish. He also argues that "City of Legions" (as applied to Chester) should be translated as "City of Floods", and that "Roodee" is from the supposed Celtic "rudh-hi", which he translates as "Dee race" (in the sense of mill-race not horse-race). He goes further in translating Flookersbrook as being derived from the Welsh for "rapid stream" and makes Mollington an "eminence above a torrent". Somewhat confusingly Boult throws in the occasional paragraph which implies that his theory is a hydraulic impossibility before going off into the realms of complete fantasy in his derivations of place names around the Wirral and Mersey: Backford becomes "the ford of swine" (from bacon).

There is often a grain of truth in folk-tales but Ashton (and Boult) seem to have taken things too far. Bala Lake's orientation can mean that severe weather and strong winds could cause overflow leading to flooding further down the Dee, so people would understand that floods could occur and might concoct tales of drowned villages on even a whole cantref. There are the remains of sunken forests on the Wirral coast, but these date from the pre-historic period. The mouth of the Gowy was prone to flooding, but there is no evidence of any significant and large-scale, permanent inundation at the end of the Roman period such as Ashton argues for. Boult even appears to suggest at one point that the passage between the Mersey and the Dee was open until 1279. Unfortunately, Ashton's influence can tend to creep in unannounced - the Wikipedia page on the Setantii features one of his maps as if it were established fact.

Chester in the "Ice Ages"

The "Ice Ages" had a massive effect upon the topography of Cheshire, so much so that a period of the "last" ice age is known as the Devensian, named after the River Dee. A great deal has been written on the glacial phenomena of western Lancashire and Cheshire, including the location of glacial spillways. During the early Devensian, ice formed only in Cumbria, but it later spread. By 22,000 BP the northwest of England was covered by ice emanating from Scotland and the Lake District. The ice sheet was warmbased, with subglacial water movement within tunnel valleys. As the climate warmed the ice receded northwards, leaving moraines and stagnant ice features. During the later stages of recession, subglacial water began to move through the thick till bed, and deformation of this sediment into drumlins occurred. This process was aided by the marine inundation of the Irish Sea basin, forming a tidewater glacier margin, and causing rapid drawdown and calving of icebergs. After the main ice sheet had disintegrated, a cold snap led to the reformation of ice in the Pennines and Lake District.

The local effects of the glacial retreat on the landscape are quite evident today: much of the Cheshire Plain is covered with a superficially level glacial till (what used to be called "boulder clay") - initially a sediment made up of unsorted, unstratified mixtures of clay, sand, gravel, silt, and boulders, with some local sorting due to water flow. The central rib of harder sandstone shows signs of now dry drainage channels which either formed under the ice or along an ice-front meeting higher ground. In places the ice formed a dam against which a freshwater lake could form. Such a lake would rise until it found an outlet and then cut a channel as it drained. It was the shells of freshwater lacrustine species which misled early geologists into believing that the mouth of the Mersey was closed by land in Roman times - the shells were of a much earlier date than was supposed.

Along the Groves at Chester the ground on both sides of the river soon rises so that the Dee flows in a very minor "gorge". This gives the name "Redcliffe" to the area. Sections of the walls of this gorge (especially on the opposite bank) seem quite steep, but this may be because stone was quarried here, possibly from as early as Roman times. These quarries, some of which have been incorporated into the gardens of the housing on the Queen's Park side, may have contributed the the belief of early antiquarians that the Normans diverted the river. It is certainly puzzling that the Dee takes a course which cuts through a low sandstone ridge rather than taking a route to the sea through Broughton. A possible explanation of this is that the Dee is here following the course of a glacial meltwater channel which provided an outlet from the Mersey towards the end of the Ice Age at a time when the mouth of the Mersey was blocked by ice. This could possibly have been a continuation southward of the Backford Gap. However, by the time the Romans arrived the hydrology around Chester was much as it is today.

Conclusions

That early cartographers misunderstood the hydrology of the Gowy/Backford Gap is forgivable. That Ormerod did not fully understand the hydrology of a watercourse on his own doorstep is curious, but he at least admits that what the early cartographers show is a puzzle and obliterated by the canal. That learned men for many years believed that the mouth of the Mersey only came into existence in Roman times is remarkable. There is now no doubt that at the end of the last Ice Age the Backford Gap was a glacial spill-way, but that it ceased to be the way that the Mersey discharged into the Irish Sea long before "recorded history". Ashton's theory that the mouth of the Mersey was closed during Roman times seems completely disproved, as is Boult's theory that the Mersey Lake lasted into the middle-ages. Ashton reasons that Ptolemy does not clearly show the Mersey and that Tacitus does not mention it, but this is a small corner of a larger "map" to Ptolemy: of no special interest, and Tacitus has no real interest in geography. The Roman bridge at Wallasey Pool can be explained by changes in sea level, and the local "traditions" that the mouth of the Mersey only opened in historic times are difficult to find, and what can be found are only legends of "floods" and "earthquakes" scattered across the region. If there has been a natural waterway linking Chester with a "Mersey Lake" in historic times it would almost certainly have left some archaeology behind.

LIDAR image of the Backford Gap and Chester. Showing how the Dee would flow through the Backford gap into the Mersey at Ince if a modest dyke (A) was constructed between Handbridge Golf Course and Blacon Point. The Roodee (R) and the Earl's Eye (E) would initially flood, as would some farmland further south.

The strangest suggestion in this strange story is mentioned briefly by Ormerod:

  • "Having thus shown that vestiges exist in the general face of the country, manifesting that the waters occupied a wider range than the present height of the tides allows, it remains to mention that a tide much lower than would suffice to cover these levels would fill the before mentioned smaller valley which intervenes between Wirral and Broxton, and render the former Hundred a complete island - as the country tradition still maintains it to have been at a distant period. The variation of level is indeed so inconsiderable that it was once proposed to take the Dee through this line into the Mersey, instead of pursuing its present artificial course by embankment; and it was in consequence of this suggestion that Mr Pennant made a series of observations which led to the connexion of the two rivers by the present canal."

No independent source for Ormerod's statement can be found in the works of Thomas Pennant (14 June OS 1726 – 16 December 1798). What Ormerod appears to refer to here is that it was actually considered to dam the Dee at Chester and redirect the whole river through the Backford Gap into the Mersey. In engineering terms this would have been just possible at the time. But this would have had major consequences for Chester: the Abbots Mead and the Roodee would flood, Edgar's Field would be underwater and the Earls Eye would become a lake. One can only speculate what the tides would do to flow in the Backford Gap.

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Backford other than the gap

Backford Gap