3i 



GEOLOGY OF THE DISTRICT AROUND 

 ORILLIA. 



General. 



The town of Orillia is situated near ihe narrows 

 between Lakes Couchiching and Simcoe, and is built in 

 part on a sandy terrace just below the Algonquin beach. 

 In the town, along the Coldwater road, which is the main 

 road leading westward, the cut bluff and boulder pavement 

 of the beach may be well seen. A mile west of the town, 

 a gravel pit shows a section across a great barrier beach 

 having an altitude of 853 feet (260-0 m.) or 135 feet 

 (41 -2 m.) above Lake Simcoe. 



North and east of Orillia the drift is relatively thin, 

 but west and southwest it becomes quite thick. A well 

 boring made in the town itself shows the surface deposits 

 to have a thickness of 170 feet (51 -8 m.). A half-mile 

 north of the station at Orillia, a cutting on the Canadian 

 Pacific railway shows well stratified sand overlain by till, 

 and a half-mile east of the station a cutting affords a 

 section through a drumlin-like ridge composed of boulder 

 clay. Northeast and east of Orillia an area of small 

 drumlins and drumlin-like ridges is developed. The 

 drumlins are generally long and narrow, and range in 

 height from a maximum of 60 feet (i8-2m.) down to 

 10 feet (3 m.) or even less, and vary in length from two 

 miles to one quarter mile or less. The longer axes of the 

 drumlins are nearly parallel and coincide with the direction 

 of glaciation, which was towards the southwest. The 

 drumlins are generally composed of sandy boulder clay, 

 showing little tr no stratification. Occasionally they are 

 seen to be, in part, composed of coarse sand and gravel 

 partially stratified, with numerous boulders and cobble 

 stones. At the north end of one of these drumlins one 

 mile (i-6km.) east of North Mara post office, along 

 Monck road, a section shows a large boulder or mass of 

 bedded Lowville limestone, which is underlain by drift and 

 was evidently glacially transported or shoved so that it 

 now rests at a steep angle on the northern slope of the 

 drumlin. The section is exposed by the face of the lime- 

 stone having been opened up as a quarry. 



No exposures of solid rocks are known to occur in 

 the immediate vicinity of the town of Orillia, but a short 



