8o 

 ANNOTATED GUIDE. 



Miles and 

 Kilometres. 



o. m. Toronto. — Alt. 254 ft. (77-2111.). Leaving 



o km. Toronto, the railway crosses the Humber 

 river immediately to the west of the city. 

 The slack water in the lower reaches of this 

 river and of the other streams at the west 

 end of Lake Ontario is due to the backing of 

 the waters of the lake owing to a differential 

 elevation of the rock basin at the eastern end 

 in post-Glacial times. The clay exposures in 

 the vicinity of the Humber consist of inter- 

 glacial materials worked over by post-glacial 

 agencies. 

 6-42 m. Mimico. — Alt. 300 ft. (91 -2m.). AtMimico, 

 10-3 km. quarries in the Lorraine shales may be seen to 

 the north of the track: exposures of the same 

 rocks occur in the bed of the Etobicoke river 

 beyond. 

 13-1 m. Credit. — Alt. 265 ft. (80 -6m.). Theinvaded 

 20-9 km. valley of Credit river is comparable with that 

 of the Humber. No rock is exposed here, 

 but in this vicinity the Lorraine shales give 

 place to the overlying red shales of the Rich- 

 mond formation which continue to Hamilton 

 and are exposed in many small valleys along 

 the line of the railway. Beyond the Credit 

 river, the north shore of the post-glacial Lake 

 Iroquois (Iroquois beach) is plainly to be seen 

 along the north side of the track all the way 

 to Hamilton. 

 31 -78 m. Burlington. — Alt. 328 ft. (99-7 m.). At 

 50-8 km. Burlington the flat bottom of Lake Iroquois 

 is well shown with the Iroquois beach beyond, 

 and above that the escarpment of the Niagara 

 cuesta. 



Just before entering Hamilton, the gravels 

 of the Burlington beach (Iroquois) may be 

 seen resting on the red Richmond shales. 

 (See guidebook to Excursion A4). At this 

 point, the Desjardins canal is crossed: it marks 

 approximately the position of a pre-glacial 

 river which discharged into the^Ontario basin. 



