No. 5.] SPENCER — SURFACE GEOLOGV. 293 



denuded, so tliat the sjucceediug Saugeeu clays lie on it uoifbrm- 

 ly. The valley of the Duudas raar.sh and Burlington bay, 

 besides such tributary streams as the Cold Spring creek were 

 excavated iu it. The Cold Spring creek excavated a channel in 

 the Erie clay a few hundred feet wide (as seen along the Ham- 

 ilton and Duudas street railway, which descends to the marsh 

 along this creek), before the deposition of the arenaceous clay. 

 In fact, a considerable portion of the Dun das valley was reexca- 

 vated by the large streams of this time. It was during this period 

 of denudation that the forest tre^s were flourishing which are found 

 under the clays and sands about the city of Toronto and in the 

 Scarboro Heights. Then came the subsidence with its deposit of 

 Saugeeu "brown clay" (described before), which covers so much 

 of the surface of the Duudas valley and in fact a great portion of 

 the Province of Ontario. During this deposit there appears to 

 have been little or no floating ice in the region of study, as there 

 is a remarkable absence of erratics. The erratics belong to later 

 date. 



The Swrboi'o Heights— Yiast of Toronto. Mr. George Jen- 

 nings Hiude has written an interesting paper. '-^ Unfortunately 



* Canadian Journal. 1877. 

 the author is a member of the more advanced school of glacial 

 thought. Over the stratified clays and sands there is a deposit 

 of what Mr. Hinde calls Till. This fills a valley of a stream 

 scooped out by a probably interghtcial stream. However, the 

 writer considers it (which he figures) as a glacial hollow (like 

 our lakes) filled up. From the evidence as laid down, it is con- 

 spicuously an old water course, and there is no evidence given to 

 show its glacial origin any more than there is evidence of the 

 gbicier excavation of the lakes. This so-called Till is composed 

 of lar drifted Trenton limestones and Utica slates. The most 

 rational description of the presence of this '' Till." is its deriva- 

 tion by coast ice from the Trenton ;md Utica rocks which 

 formed the shores to the north artd east. 



Closing Remarks on the Glacial Thcury. — In the Dundas val- 

 ley there are a number of sheep backs or roches moutonnies. The 

 summits of these hills, at least, belong to the Terrace epoch, and 

 may be easily explained b}^ the denudation by streams, owing to 

 the peculiar features of the country, which will again be noticed. 



The Cause of the Arctic Winter is a question outside of this 

 short descriptive study. However, the theory of the "secular 



