KENDALL : PLEISTOCENE MOLLUSCA IN NORTH HUNTINGDOKSHIRIC. 



solution of this and other points.^ , So remembering that we are here 

 just outside the Hmits of the great ice-sheet which in the glacial age 

 over-spread the north and midlands, I hold on the present evidence 

 that this deposit is of lacustrine origin, laid down in a lake of some 

 considerable extent of the Pleistocene period, perhaps formed and 

 fed by the glacial streams of the great Ice Age. 



§ I.— THE CONTENTS OF THE SHELL-DEPOSIT. 



A. —The Terrestrial Species. 



I propose to group these species under three heads — I. Those which 

 are of a distinctly Boreal type, whose range to-day is more or less 

 confined to the sub-Arctic region. II. Those which, while not so 

 definitely Arctic, are still of a somewhat northerly range. III. Those 

 species which have a more southerly range. 



I. — Definitely Boreal Species. 

 Pyramidula rudeyata Studer 

 -Acanthinula acukata MiiUer 

 Vertigo minutissima Hartmann 

 V. antivertigo Drap. 



Abundant and very fine. 

 Plentiful. 



V. pygmcea Drap. 

 V. pusilla Miiller 

 V. august ior Jeff. 

 Clausilia veiitricosa Drap. 

 CI. puniila Ziegler 



II. — Specles with 



Vitrea crystallina Miiller . 

 V. nitidula Drap. 

 Punctum pygmcziiin Drap. 

 Pyramidula rotundata Aluller 

 Hygromia hispida L. 

 Vallonia pukheUa MiiUer 

 V. costata Miiller 

 Helicigona arbustorunt \j. 

 Cochlicopa lubrica Miiller, and 



var. lubricoides Fe'russac 

 Azeca tridens Pulteney 

 Pupa muscoruin L. 

 Carychium minimum Miiller 



Most of the Vertiginid?e are 

 present in considerable 

 numbers. 



Two specimens. 

 Abundant. 



Northerly Range. 



Plentiful. 

 Scarce. 

 Abundant. 

 Abundant. 

 Very abundant. 

 Very abundant. 

 Very abundant. 

 Scarce. 



I Very abundant. 



Abundant, 



Comparatively scarce. 

 Very abundant. 



I The workman who did the borings in the neiglibourhood to find the general extent of this 

 Buried Lalce informs us that in several places the deposit underlies patches of Boulder Clay. 

 This fact is of great interest and importance and we hope to have confirmation of it, which would 

 establish beyond question the actual age of the deposit. 



