00 THK K'K A(1E IX CANADA. 



sand was deposited. It is usually, indeed, in tliis ])fisiti()n 

 that the ,t,a'eatei' ])art of the shells of our l'osl-])liocene 

 beds occur: the, Saxicava sand heinti; generally somewhat 

 barren, or containinif only a few shallow-water s'leeies, 

 while tlu! LiMJa clay is usually also somewhat scantily 

 su})])lie(l with shells, except toward its upper layers. 

 Hence it is somewhat diHieuh to ri'fer a lar^^e part of the 

 shells to (iither dejiosit. 1 have, however, usually 

 retjarded the; richly fossiliferous deposit as bidonging to 

 the L(Mla clay: and where, as sometimes hap])ens, tlie 

 clay itself is absent and merely a thin layer rich in 

 fossils separates the Saxicava sand from the ])oul(ler-clay, 



1 liave regarded this layer as the rei)resentative of the 

 Leda clay. AVhere, on the other hand, the Leda clay is 

 thick and well dcvelo])ed, it admits of sub-division into a 

 loifcr Leda clay, unfossiliferous or with oidy shells of Tjcda 

 glaciali)i and Macoina Gra>,nl((n<Hra, and an upper Lnhi 

 clay, usually more sandy and holding a rich boreal fauna 

 identical with that of the northern ])art of the gulf and 

 river St. Lawrence at present. 



The Saxicava sand, in tyi)ical localities, consists of 

 yellow or brownish (piartzose sand, derived ])robably from 

 the waste of the Potsdam san<lstonc and Lauren tian 

 gneiss, and stratified. It often contains layers of gravel, 

 and sometimes is represented altogether by coarse gravels. 

 It is somewhat irregular in its distril)ution, forming banks 

 and mounds, partly no doubt in consequence of original 

 irregularities of deposit, and partly from subsequent 

 denudation. In some outlying localities it is lial)le to be 

 confounded with the modern 'iver sands and gravels. 

 Large travelled Ijoulders oftc.i occur in it; but it rarely 

 contains glaciated stones, the stones and pebbles seen in 

 it being usually well rounded. 



