30 



Kilometres ^ broad flat-bottomed valley extends west- 



ward for a number of miles from the head of 

 the bay, and is floored by a considerable 

 thickness of sands and gravels derived from 

 the Algonquin beach, which has an altitude, 

 at the town of Barrie, of 785 feet (239.6 m.). 

 The sides of the valley are composed of drift, 

 and rise steeply to an altitude of over 200 

 feet (60.9 m.) above the valley bottom. 

 The record of a well boring, made near the 

 town of Barrie, shows the surface deposits to 

 have a thickness of 335 feet (102 . 1 m.) below 

 the level of Lake Simcoe at which point the 

 Trenton limestone was struck. The boring 

 continued through 200 feet (60.9 m.) of the 

 limestones of the Trenton, Black River and 

 Lowville formations to the Pie-Cambrian. 

 The deep borings mentioned above as having 

 been made in the drift deposits at Thornhill, 

 Bradford and Barrie, together with several 

 others made in the district, confirm the ex- 

 istence of a deeply drift-filled pre-glacial valley 

 connecting the basins occupied by Georgian 

 bay and Lake Ontario, the probable existence 

 of which was pointed out by J. W. Spencer. 



Between the towns of Barrie and Orillia, 

 a distance of about 25 miles (40.3 km.), the 

 Algonquin beach is well developed and can 

 be followed with nearly perfect continuity all 

 the way. Throughout the greater part of 

 the distance, the railway follows along almost 

 at the same altitude as the bea h. At 

 Hawkestone, about 14 mlies (22.5 km.) north 

 of Barrie, the bluff and boulder-strewn terrace 

 of the ancient shorelin: may be seen a short 

 distance west of the station at an altitude of 

 821 feet (250.2 m.). 

 86.0 m. Orillia. Alt. 724 feet (320.7 m.). 



138.5 km. 



