BEACHES, ETC., OF THE SOUTH OF ENGLAND. 



301 



Table (continued). 





Portland 



(Gwyn 



Jeffreys). 



Torquay 

 (A. R. 



Hunt). 



Bridg- 

 water (W. 

 Baker). 



Barnstaple 

 JBay(G. 

 Jeffreys). 



Univalves {continued). 



Nassa reticulata, Flem 



incrassata, Miill 



Natica Alderi, Forbes 



Patella vulqata,Tj 



* 

 •if- 



* 



* 

 ■»• 

 * 

 * 

 * 



* 

 * • 





it 

 * 



* 



* 

 * 



Pleurotoma striolata, Phil. 



~ hrachy stoma, Phil. . . . 



turricula, Mont 



Purpura lapillus, L/ 



Eissoa parva, Da Costa . . . 

 striata, Phil 





suhcylindrata, Jeff. . . . 



Scalaria Turtona, Turt. ... 

 SJcenea j^lanorhis, Fabr. ... 

 Tectura virginea, Miill. ... 



Trochus zizyphinus, L 



lineatus, De Blainv. . . . 



helicinus, Gml 



umbilicatus. L 



* 



Tropkon truncatum, Strom. 



Turritella terehra, L 



TJtriculus truncatulus, Brug. 



3. Other Forms. 

 Serpiila 



£alanus crenatus . ... 



Miliola seminulum 









Of the total of 64 species, only 39 are common to the Glacial 

 drifts of the ISTorth of England and Wales. Of these, 27 are found 

 at Moel Tryfaen, 31 in the lower Macclesfield beds, and 28 in the 

 Upper Boulder Clay of JSTewton. 



The total number of species of the Glacial drifts in the districts 

 above-named amounts, according to the lists of Mr. De Eance ^ and 

 Mr. "W. Shone,^ to 98. Allowing for the circumstance that in the 

 one case the shells are almost entirely those of the littoral zone, 

 whilst in the other we have the product of various zones of depth 

 (still the littoral zone is represented in the Glacial Series), it is 

 obvious that a marked difference in the temperature of the seas is 

 indicated by the difference in the mollusca. There is the absence 

 also in the Raised Beaches of such northern shells as Astarte 

 borealis, Leda jpernula, Fusiis islandims^ Natica groenJandica, and 



^ ♦ The Superficial Geology of Lancashire,' Mem. Geol. Survey (1877), p. 128. 

 ^ *0n the Glacial Deuosits of West Cheshire,' Quart. Journ. Geol. Soc. 

 vol. xxxiv. (1878; p. 394. 



