116 T.M. Reach— Tod-Glacial Geology of 



tula, N. diclyma, N. Westii and Pleurosigma Balticum. The evi- 

 dence of marine origin is almost everywhere of the most conclusive 

 character, though probably not accessible to all observers. 



The blue clay, locally known as " Scotch," varies from a tenacity 

 suitable for making bricks to that of a looser or more silty and sili- 

 ceous character. This laminated clay has evidently been laid down 

 in quiet waters or embayments, and, in boring through it, it invari- 

 ably, if of sufficient depth, gradually passes into a fine siliceous silt. 

 In certain localities, as between the Alt mouth and the sub-marine 

 forest, are local beds of sand ; and the nature of the beds in other 

 places passes from sand through silt to blue clay. For these reasons, 

 a comprehensive term is desirable, and I have therefore proposed to 

 call them the Formby and Leasowe Marine Beds. The one name 

 representing Lancashire and the other Cheshire — both places being 

 central in their respective districts. The depth of the deposits in 

 places exceeds 70 feet, and, having levelled up the beach and valleys 

 of the Boulder-clay, that portion inland of high- water mark is repre- 

 sented, I should say, by the space included between the Boulder-clay 

 base and a horizontal plane about 10 feet above Ordnance datum. 



The most frequent mammalian remains found in these beds, but 

 which are also common to the overlying peat-bed and recent 

 silts, are those of the Cewus elaplms or red deer. There have 

 also been found in both the skulls of £os longifrons, Bos 

 primigenius, and bones of a small variety of Uquus, and of the 

 dog or wolf. Bones of Cetaceans occur, as far as I have been 

 able to ascertain, only in the recent silts. From physical reasons 

 I some time since .came to the conclusion that these deposits 

 had taken place when the land was relatively lower to the sea than 

 now ; and having found at Leasowe, below the superior peat-bed, a 

 bed of Scrobicularia piperata, evidently where they had lived and 

 died, at about high-water mark of spring-tides, this fact seems to 

 conclusively settle the matter. I am, therefore, of opinion that high- 

 water mark was then at or about the 25-feet contour line. The area 

 of these deposits, exclusive of those in the Mersey itself, is in Lanca- 

 shire about 75 and in Cheshire 7J square miles, the same as previously 

 stated, for the whole series of these deposits on the coast, below the 

 25-feet contour line, and inland of high-water mark. 



Superior Feat and Forest Bed. — After the Formby and Leasowe 

 marine- beds had been laid down^ the land became gradually elevated 

 and subject to sub-aerial influences, which partially moulded and 

 modified the form of the now dry land. The sea would leave the 

 surface in long undulations, thereby determining to some extent the 

 water-beds and new river valleys, though the persistence of the old 

 valleys is certainly remarkable. The cutting of the back drain at 

 Crossens discloses what is evidently an old river-bed, now 

 silted up, the bottom of which is certainly not less than 10 feet 

 below Ordnance datum, and therefore considerably below the bed 

 of either the Alt or Douglas, and probably drained the site of 

 Martin Mere and a large extent of country to the southward. 

 This river-bed, at the point named, is cut through the Boulder- 



