500 REVIEWS 



A former level of the Great Lakes lower than the present is shown by the follow- 

 ing lines of evidence: (i) by stumps along the Lake Erhe shore west of Port Rowan 

 with their roots in soil below lake level; (2) by tree trunks in a layer of clay and 

 marl in the mouth of Maitland River at Goderich 10 to 15 feet below the level of Lake 

 Huron; (3) streams discharging into Lakes Huron, St. Clair, Erie, and Ontario have 

 their lower courses flooded from the lakes. In the case of the Thames and the Syden- 

 ham the depth of flooding is 10 to 25 or 30 feet, and extends for several miles up 

 the stream. 



Spits and dunes on the north shore of Lake Erie are being built mainly by winds 

 that blow from the southwest, those on the north shore of Lake Ontario by winds 

 blowing from the east. 



Coleman, A. P. Marine and Freshwater Beaches of Ontario. Bull. Geol. 



Soc. Amer., Vol. XII, pp. 129-46, igoi. 



Marine deposits and shell-bearing gravel and sand extend up the St. Lawrence 

 valley to Brockville, both on the Ontario and New York side, but have not been found 

 farther west, though the same body of water is known to have extended into the 

 Ontario basin. Plant remains found in clay nodules in Ottawa are those of a cool- 

 temperate climate like the present climate of that region. The remains of marine 

 animals are of species found now in the Gulf of St. Lawrence. 



Higher shore lines are found, and other evidences of static water at high levels, 

 but the author doubts if any of these higher shore lines are postglacial and marine. 

 On the contrary, they appear to have been produced by glacial lakes. In some cases 

 the beaches contain fresh-water fossils. 



Attention is called to evidences of northward differential uplift in the Great Lakes 

 region, and it is considered probable that the highest beaches were formed at a com- 

 paratively slight altitude above the sea. The objection raised against ice-dams, that no 

 glacial mass could withstand the pressure of a head of water hundreds of feet in depth, 

 may find no application here if the land was relatively low, and is thought to be of 

 doubtful pertinence even under conditions of high altitude. 



Coleman, A. P. Sea Beaches of Eastern O^itario. Rept. of Ontario Bureau 



of Mines for iqoi, pp. 215-27. 



Describes the character and distribution of the sea beaches and the faunas which 

 they contain. Also gives a few observations on the Leda clay and the Saxicava sand. 



Coleman, A. P. Iron Ranges of the Lower Huronian [Ontario]. Rept. of 



Ontario Bureau of Mines for 1901, pp. 181-21 1. 



Although dealing chiefly with the iron-ore bodies, a brief discussion of the 

 Pleistocene geology is presented. 



Coleman, A. P. Glacial and Interglacial Beds near Toronto. Jour. Geol., 



Vol. IX, pp. 285-310, 1901. 



Presents a connected history of events in the Ontario basin from the retreat of the 

 lowan ice-sheet, which is summed up as follows : 



1. Retreat of the lowan ice-sheet. 



2. Interval of erosion, with water probably lower than at present. 



3. Don stage, warm-climate trees, and Mississippi unios, water dammed by 

 differential elevation toward the northeast to 60 feet above the present lake. 



