KENDALL : PLEISTOCENE MOLLUSCA IN NORTH HUNTINGDONSHIRE. 9I 



chology, and who has been for a period of years consistently my 

 guide, philosopher and friend in matters conchological, and the more 

 justly so as he was the first to point out to me that this shell was quite 

 distinct from all the known British Pahidestrinidce. 



7, Unio littoralis Lamarck. 



This large bivalve occurs frequently in the deposit in a more or 

 less fragmentary condition, coming out in large scales of frj^gile, bright 

 pearly material. Unfortunately my trowel pierced right through the 

 two perfect specimens which I have met with, but the marl held the 

 fragments together sufficiently for me to identify the species. It is 

 of frequent occurrence in British Pleistocene deposits. In the imme- 

 diate neighbourhood it was recorded many years ago by Dr. H. 

 Porter, F.G.S., of this city from the Pleistocene gravels of the old 

 Nene River, who figures it in his book "The Geology of Peter- 

 borough," published in 1861. 



My best thanks are due to Mr. J. D. Dean for a large amount of 

 help in separating out the species in the first place and also for the 

 measurements given in this paper, also to Mr. A. S. Kennard for the 

 final determination of the species ; his extensive knowledge of 

 British PJeistocene forms has made his help and kind advice abso- 

 lutely invaluable. I have alscr to thank Mr. B. B. Woodward who 

 kindly separated out and named the Pisidia for me, also Mr. Roebuck 

 and Mr. Tomlin for their consistently kind advice and aid, and Mr. 

 Edward Collier for the loan of a number of continental Helicdia 

 which have materially assisted in the identification of the Helicella 

 found in the deposit. 



Vertigo substriata in Guernsey. ^The discovery of Vertigo suhsiriala m the 

 Channel Islands materially extends its range, and renders it all the more probable 

 that it will be found in some of the southern counties where it has not yet been 

 detected. The locality where it occurs in Guernsey is a marshy spot on the cliffs 

 at St. Martin's, where a little rivulet runs down the cliffside through a small patch 

 of loose stones interspersed with vegetation — perhaps a dozen yards long and half 

 as wide. The slope of the ground prevents the stones from being entirely sub- 

 merged even jn wet seasons, and the place is never quite dry in summer time. It 

 must be now some twenty years since I discovered that this little marshy spot was 

 the home of Pupa anglica and Vertigo antivertigo, both of which species occur 

 there in great profusion. During a visit to Guernsey last August I took my son to 

 this spot to get these two species, and it was while collecting them that we found 

 V. substriata. Curiously enough, altliough the marsh is very small, this minute 

 shell seems to be restricted to one part of it, but there it occurs quite plentifully 

 under the wet stones. I am indebted to Mr. J. E. Cooper for kindly examining 

 specimens, and confirming the name. I may just mention incidently that in the 

 same marsh, among the stones, may be taken in numbers one of the very rarest 

 of British spiders, Saiticus forinicarius, which closely resembles an ant. — E. D. 

 Marquand {^Rcad before the Society, Nov. 13th, 1912). 



