“Wasting Effects of the Sea on the Shore of Cheshire between the Rivers Mersey and Dee. (Read before the Wernerian Society, 8th March 1828.)
“On a former occasion I had the honour to make a few observations which appeared in the second volume of the Society’s Memoirs regarding the encroachment of the sea upon the land generally. The present notice refers only to that portion of the coast which lies between the rivers Mersey and Dee, extending to about seven miles.
“To this quarter my attention, with that of Mr. Nimmo, Civil Engineer, had been professionally directed in the course of last month. In our preambulatory survey we were accompanied by Sir John Tobin and William Laird, Esq., of Liverpool, along the Cheshire shore and its connecting sandbanks between Wallasey Pool in the Mersey, and Dalpool in the river Dee.
“Within these estuaries the shores may be described as abrupt, consisting of red clay and marl, containing many land or boulder stones of the cubic contents of several tons, and very many of much smaller size, diminishing to coarse gravel. But the foreland or northern shore between these rivers, which I am now to notice, is chiefly low ground, and to a great extent is under the level of the highest tides. The beach or ebb extends from 300 to 400 yards seaward, and toward low water mark exposes a section of red clay; but toward high water it consists of bluish coloured marl, with peat or moss overlaid by sand. This beach, at about tide level, presents a curious and highly interesting spectacle of the remains of a submarine forest. The numerous roots of trees, which have not been washed away by the sea, or carried off by the neighbouring inhabitants for firewood, are in a very decayed state. The trees seem to have been cut off about two feet from the ground, after the usual practice in felling timber, and the roots are seen ramifying from their respective stumps in all directions, and dipping towards the clay subsoil. They seem to have varied in size from eighteen inches to perhaps thirty inches in diameter, and when cut with a knife appear to be oak. Several of the boles or trunks have also been left upon the ground, and being partly immersed in the sand and clay, are now in such a decomposed state that, when dug into with a common spade, great numbers of the shell fish called Pholas candida, measuring about three fourths of an inch in length and two inches in breadth, were found apparently in a healthy state. These proofs of the former state of this ebb or shore—now upwards of twenty feet under full tide—having been once dry land to a considerable extent beyond the region of these large forest trees were rendered still more evident by the occurrence of large masses of greenstone, which, at a former period, had been embedded in the firm ground here, and especially on the shore within the river Dee. It may further deserve notice that the inhabitants of this district have a traditional rhyme expressive of the former wooded state of this coast, where not a tree is now to be seen, viz., “From Birkenhead to Helbre a squirrel may hop from tree to tree;” that is, from the Dee to the Mersey, now presenting a submarine forest.
“As these evidences of great changes upon the state and former appearances of the land were highly interesting to the party, and intimately connected with the professional inquiries of myself and colleague, it seemed desirable, if possible, to get them corroborated by oral testimony. Sir John Tobin accordingly very obligingly took measures for examining the oldest people in the neighbourhood as to their recollection of the former state of these shores. In particular, Thomas Barclay, aged ninety-three, “all but two months,” by profession a mason and measurer of country work; Henry Youd, labourer, aged eighty-six; and John Crooksan, labourer, aged eighty, were examined. Barclay stated that he had been employed at the erection of the Leasowe landward lighthouse in the year 1764; that there were then two lighthouses near the shore, for a leading direction to shipping through the proper channel to Liverpool; and that the seaward light became uninhabitable from its being surrounded by the sea. A new light was then built upon Bidstone Hill, and the present Leasowe Lighthouse, formerly the landward light which he had assisted in building, became the sea light. He could not condescend upon the distance between the two original lights, but was certain that it must have been several hundred yards; that he knows that in the course of thirty years the shore of the Leasowe lost by measurement eleven Cheshire roods or eighty-eight yards; and verily believes that, since he knew this shore, it has lost upwards of half a mile of firm ground. To the correctness of these statements the other two aged men gave ample testimony, Henry Youd having also worked at the lighthouse.
“As to the present state of things, the party alluded to were eye-witnesses of the tides on the 16th, 17th, and 18th of February 1828, having exhibited a very alarming example of the encroachment of the sea upon the Leasowe shore. At high water it came over the bank, and ran in a stream of about half a mile in breadth surrounding the lighthouse, and continued its course through the low grounds toward Wallasey Pool on the Mersey, thereby forming a new channel, and threatening to lay several thousands of acres of rich arable and pasture lands into the state of a permanent salt lake. The present Leasowe Lighthouse, which, in 1764, was considered far above the reach of the sea, upon the 17th of February last was thus surrounded by salt water, and must soon be abandoned unless some very extensive works be undertaken for the defence of the beach, the whole of the interior lands of the Leasowe being considerably under the level of high water of spring tides.
“This coast, with its sandbanks in the offing, its submarine forest, and the evidence of living witnesses as to the encroachment of the sea upon the firm ground, is altogether highly interesting to the geological and scientific inquirer. The remains of forests in the bed of the ocean occur in several parts of the British coast, particularly off Lincoln, on the banks of the Tay near Flisk, at Skail in the mainland of Orkney, and in other places noticed in the Transactions of this Society, and are strong proofs of the encroachments of the sea upon the land. However difficult, therefore, it may be to reconcile the varied appearances in nature regarding the sea having at one time occupied a higher level than at present, yet its encroachment as a general and almost universal principle seems to be beyond doubt in the present day.
“Since I had last the honour of addressing the Society on this subject, opportunities have been afforded me of making many additional observations on the British shores, and of personally extending these to almost every port on the Continent between the Texel and the Garonne. I have also, through the obliging communications of friends, been enabled to extend my inquiries to other quarters of the globe, and I am now prepared to state that, with a few comparatively trifling exceptions, the sea appears to be universally gaining upon the land, tending to confirm the theory that débris arising from the general degradation of the land, being deposited in the bed of the minor seas, is the cause of their present tendency to overflow their banks.”