26 Posl-PUocene Deposits of the St. Lawrence. 



and gravel, equivalent to the Saxicava sand of Montreal, and 

 resting on boulder clay. The overlying mass is filled with Saxi- 

 cava Tcllince, &e. ; and the underlying boulder clay as usual 

 contains no fossils. My experience in the Montreal deposits, 

 however, led me to expect a bed, however thin, representing the 

 Leda clay, between these ; and on searching at the junction of 

 the two great beds above mentioned, I was gratified by finding a 

 layer of sand about three inches in thickness, filled with the rarer 

 shells of the deposit, characteristic of its deeper waters, such as 

 Fusus tornatus,PecttnIsla>idicus, Baccinum ciliatum, Modiolaria 

 discors, etc.* Tiie Rhyncondla psittacea occurs only in this layer, 

 and in such a manner as to leave no doubt that it is buried here 

 in situ, in the very spot where it lay anchored to the stones of 

 the surface of the drift. On these stones, however, I found a new 

 and interesting field for observation. In the thin layer above 

 referred to, all the stones, as well as those that lay on the surface 

 of the boulder clay or partly imbedded in it, were covered with 

 the remains of marine creatures, especially Balanus crenatus, 

 Spirorbis sinistrorsa,Spirorbi8 spirit! am, Lepralia andHippothoa. 

 This layer, in short, evidently represented a time when the sur- 

 face of the boulder clay, covered only by a thin layer of sand and 

 stones, constituted the bottom of clear and deep water, before it 

 became covered by the Saxicava sand. This bottom, although 

 no clay has been deposited on it, represents the Leda clay at 

 Montreal, and is exceedingly rich in the fossils usually found 

 at the surface of that bed. Foraminiferx occur in it, but they 

 are comparatively rare, and, so tar as I could find, only of spe- 

 cies common at Montreal. 



(2.) Species of For aminif era. 



In my paper of last year a few of these were figured, but the 

 nomenclature of these creatures was in a state so unsettled that 

 I hesitated to attach names to them or to identify them with 

 described species. I am now relieved of the greater part of this 

 difficulty by the appearance of Williamson's excellent monograph 

 on the British Foraminifera, the nomenclature of which I shall fol- 

 low in noticing our Canadian species. 



* Sir C. Lyell notices the fact that these shells are more abundant in 

 the lower part of the mass than above. 



