490 T. MelZard Reade— Oscillations of Level of Land. 



in great abundance. At Cook's Lane, Great Crosby, 3 lbs. of clay 

 yielded to Mr. Joseph Wright 900 of one species, viz. Nonionina 

 depressula, 1 and the clay in the cuttings of the Seacomhe Branch of 

 the Wirral Railway yielded them plentifully. 2 All these clays 

 contain boulders in varying proportions, mostly of Lake District 

 Silurians, andesitic lava and ash, Eskdale granite and Buttermere 

 granophyre, together with much Carboniferous Limestone and some 

 flints. These are usually planed and striated, often intensely so. 

 Very large erratics of similar rocks are also met with. One now in 

 Sefton Park, dug out of the foundations of a school at Edgehill, of 

 andesitic ash, weighs about six tons. One boulder of Carboniferous 

 Limestone which I got in a brick-pit at New Ferry is bored with 

 Saxicava, many of the valves being still in the holes in situ. It is 

 also striated. Intercalated in the Boulder-clay are beds of sand and 

 gravel, of which, perhaps, the best-known example is at Blackpool, 

 where the Boulder-clays and sands as proved by boring are nearly 

 200 feet thick and rest on the Keuper Marls. In connection with 

 the intercalated sand-seams are sometimes to be seen indications of 

 shore action, as in the cuttings of the Wirral Railway before 

 mentioned. Here a sand-bed of a few feet thick is intercalated 

 in the clays and covers a large area. It is full of clay spheres and 

 spheroids, evidently boulders of the Boulder-clay rolled on the 

 beach of sand and sand-coated. Experiments made by Mr. T. W. 

 Davies, E.Gr.S., show that it was impossible to coat a ball of the 

 clay hy rolling it in sand under water, but rolled in damp sand it 

 quickly took up a shield of sand and shell fragments; hence we both 

 of us inferred that the sand-bed represented an ancient shore. 



The Boulder-clay, as already observed, rests in this neighbourhood 

 upon the Trias, either Keuper or Bunter, and if the rock be of 

 a nature fit to receive striae they are usually found upon it, being 

 generally in a north-westerly direction, though they frequently 

 cross each other at an angle even in the same example, and at 

 Millers Bridge I found cross striae approaching a right angle. If 

 the rock be soft it usually either grinds into sand or sand and rubble. 

 I have never succeeded in finding a boulder lying upon the rock of 

 which it could be said the strias were due to it, but this may arise 

 from the difficulty of making the observations. The surface of the 

 Triassic rocks under the Boulder-clay without doubt represents 

 a land-surface still older than the land-surface at the top of the 

 Boulder-clay or that of the peat and forest bed. The evidence of 

 this is the subaerial erosion which has shaped its orographic forms 

 and the river-channels now filled up with Boulder-clay which 

 ramify below the present surface. Such a pre-Glacial valley was 

 proved to exist in the Mersey filled with Boulder-cla}', which was 

 predicted by me in 1873, and proved by the Mersey Tunnel 

 twelve years afterwards. If the clay and sand deposits were 



1 " Foraminiferal Boulder-clay, Great Crosby": Proceedings of Liverpool 

 Geological Society, Session 1895-6. 



2 Proceedings of Liverpool Geological Society, Session 1S94-5. 



