SECTIONS OF PLEISTOCENE DEPOSITS. 



313 



The observed sequence of deposits may be understood by the subjoined 

 sections, which represent respectively the arrangement in the St. Lawrence 

 valley at and below Montreal as observed by the author ; that on the north 

 shore of Lake Ontario as given by Dr. J. G. Hinde ;* and that in the vicinity 

 of the Belly river, North West Territory, as noted by Dr. G. M. Dawson.f 



Montreal and lower St. 



Lawrence. 



J. Wm. Dawson. 



a 



o 

 o 

 o 





I. 



Surface soil, post-Gla- 

 cial alluvia and peat. 



II. 



Surface bowlders, Saxi- 

 cava sand and gravel. 

 Bowlders in and below 

 sand. 



III. 



Upper Lcda. clay, ma- 

 rine shells, and drift 

 plants. Lower Leda clay, 

 marine shells, and drift 

 plants. 



IV. 



Lower bowlder clay or 

 till. Many native and 

 some traveled bowlders. 

 A few marine shells of 

 arctic species. 



V. 



Paleozoic rocks, 



striated. 



often 



North shore of 

 Ontario. 

 J. G. Hinde. 



Lake 



Surface soil, stratified 

 sand, and gravel. 



II. 



Bowlders, sand, etc. 

 Laminated clay. Bowl- 

 der deposit. 



III. 



Stratified sand and 

 clay, with fresh-water 

 shells and plants. 



IV. 



Lower bowlder clay or 

 till. Native and traveled 

 bowlders. 



Paleozoic rocks, often 

 striated. 



Belly river, North 



Territory. 



G. M. Dawson 



West 



Surface soil and prairie 



alluvium. 



II. 



Upper bowlder deposit. 



III. 



Gray sand with iron- 

 stone nodules. Brownish 

 sandy clay. Carbonaceous 

 layers and peat. Gray 

 sand and ironstone. 



IV. 



Lower bowlder clay. 

 Many traveled bowlders. 



Probably Cretaceous 

 beds. 



The above sections show a general correspondence in the series of deposits, 

 except that in the sections on Lake Ontario, especially in that at Scarboro' 

 heights studied by Hinde, we find a division of the upper bowlder deposit 

 not so evident in the other sections. 



There is no reason to doubt that the three members of the Pleistocene 

 indicated as II, III, and IV are approximately contemporaneous in the 

 different districts, and that No. Ill represents the usual interglacial period 

 throughout North America. At the same time it is to be observed I 1) that 



* Canadian Journal, 1877, p. 339, et seq. t Keport Geol. Survey of Canada, L884, p. 1 1 1 O, et seq. 



