80 Notices of Memoirs — J. Lomas — Worked Flints in Drift. 



ashy beds. The felstone shows lines of flow parallel to its side, and 

 in some places is rudely columnar, the axes of the prisms being 

 perpendicular to the side of the dyke. It is owing to this ai'range- 

 ment of the columns, and of the lines of flow, that I consider the 

 rook to be a dyke. I call it a dyke because of the straightness of 

 its sides ; but it is rather a boss than a dyke, as, while it is two 

 hundred yards wide, it is only about three or four hundred yards 

 long. The rock is not like any of the lower Snowdonian felsites 

 occurring in the immediate neighbourhood, but it is decidedly like 

 the upper felstone, which forms outliers on Crib Goch and Crib y 

 Ddysgl. It seems to me that we have here the source of the upper 

 felsitic lava of the Snowdon district. The boss is a plug of rock 

 consolidated in and filling up the orifice through which the upper 

 lava flowed to the surface. 



VIII. — On Worked Flints from Glacial Deposits op Cheshire 

 AND THE Isle of Man.^ By J. Lomas, A.R.C.S., F.G.S., 

 Pres. Liverpool Geol. Soc. 



FLINTS are not common in the glacial deposits of N.W. England. 

 In one or two places in the Wirral, however, and in the Isle 

 of Man, they are fairly plentiful. Sometimes they occur in the 

 Boulder-clay, but more frequently in Glacial Sands and Gravels. 

 Some of the flints collected in these localities show undoubted signs 

 of human workmanship. 



Prenton, Birkenhead. — The flints exhibited were collected from 

 a recent excavation near Mount House. Soft Bunter is seen on the 

 south and west faces overlain by glacial sands. Between the two lies 

 a bed of gravel containing small Lake District and Scotch erratics 

 up to six inches in diameter, along with broken Triassic rocks, clay 

 galls, and marine shells. In this gravel most of the flints have been 

 found. Others occur in the overlying sand, which also contains 

 erratics and shell fragments. Similar sand occurs at many places 

 in the immediate neighbourhood, and is usually overlain by 

 Boulder-clay. 



Spital Sandpit. — False-bedded clean sand is seen, containing 

 gravel and rolled cla}' galls, overlain by tough Boulder-clay. The 

 flints occur both in the gravel and Boulder-clay. 



Capenhurst. — Flints collected from gravel bands and clay in old 

 sandpit opposite church. 



Mollington, near Chester. — The large sandpit, near high road, 

 contains very little gravel, and the flints mostly occur in the 

 Boulder-clay which caps the section. 



Cliffs north of Ramsey, Isle of Man. — Glacial deposits in north of 

 island well exposed in the fine cliffs which extend from Ramsey 

 almost to the Point of Ayre. Near Ramsey, sanSs and gravels 

 predominate, and these get successively more and more clayey 

 towards the north. 



In collecting the flints I took great care to separate those found in 

 the talus slopes from those actually in the clays and gravels. The 

 flints are exhibited and speak for themselves. 

 1 Eead before Sect. C (Geology), British Association, Bristol Meeting, Sept. 1898. 



