386 



W. SHONE ON THE GLACIAL DEPOSITS OE WEST CHESHIRE. 



Mackintosh (Quart. Journ. Geol. Soc. vol. xxviii. p. 388), is not 

 exposed at the base, and therefore cannot be compared with this 

 section ; but Mr. T. Mellard Reade, F.G.S., in his excellent paper 

 on the " Drift-beds of the North-west of England " (Quart. Journ. 

 Geol. Soc. vol. xxx. p. 27), describes the Lower Boulder-clay of 

 Liverpool as possessing very similar characteristics. 



The Fauna of the Drifts. 



Having briefly noted the physical characteristics of these drift- 

 deposits, the still more interesting subject, the fauna, remains to be 

 discussed. The Upper Boulder-clay of the Newton section has 

 yielded a great number of species, not, however, because the shells 

 are more abundant than usual, but in consequence of the extent and 

 duration of the exposure. The period of collection extended over 

 about five years, and all the specimens have been picked from the 

 clay by myself, with the exception of one Natica sordida, found in 

 my presence by J. B. Manning, Esq., Constable of Chester Castle. 

 Some thousands of fragments were thus obtained, which have been 

 submitted from time to time to J. Gwyn Jeffreys, Esq., LL.D., 

 E.R.S., E.G.S., who has examined and named them. I cannot 

 sufficiently express my thanks to that gentleman for his uniform 

 courtesy and kindness in having undertaken so much difficult and 

 tedious labour. 



Of the fifty-six species and varieties which occur in the Upper 

 Boulder- clay of Newton, the following are known to be living in 

 Arctic and Scandinavian seas, but are not as yet admitted to be 

 living on the British shores : — 



Leda pernula. 

 Astarte borealis. 

 Tellina calcarea. 

 Dentalium striolatum. 



Natica affinis. 

 Admete viridula. 

 Pleurotoma pyramidalis. 



The following Mollusca found at Newton are living in British 

 seas, but belong to the northern type of our fauna, as they inhabit 

 Arctic and Scandinavian seas in common with our own : — 



Mytilus modiolus. 



Cyprina islandica. 



Astarte compressa, var. striata. 



Lacuna divaricata. 



Buccinum undatum.' 



Trophon clathratus, var. truncata. 



Pleurotoma rufa. 



turricula. 



The following Mollusca found at Newton are living in British 

 seas, and belong to the southern type of our fauna : — 



Area lactea. I Natica sordida. 



Venus chione. 



The remaining thirty-eight species found at Newton are not pro- 

 nounced either northern or southern forms, and do not therefore 

 indicate any particular climatic conditions. 



In the Middle Sands at Upton, out of twenty-three species found 

 jointly by Mr. Shrubsole and myself, two are Scandinavian, Astarte 

 borealis, Dentalium striolatum, and four British, but of northern 

 type, viz. Mytilus modiolus, Cyprina islandica, Buccinum undatum, 



