GEOLOGY OF THE SCHROON LAKE QUADRANGLE 65 



Most of the beds are from 6 inches to 2 feet thick with stratification 

 surfaces between them very evident. Such beds are in nearly every 

 way like those above described as occurring just north of the 

 steamer landing. Chert is often present. Kemp, in the paper 

 above referred to, states that " thin sections of the chert merely 

 exhibit a brown, nearly isotropic base with numerous rhombohedra 

 of calcite or dolomite scattered through it." Some relatively thin 

 layers are, however, very sandy. Considering the strike, dip and 

 location of this section and the one just north of the steamer 

 landing, it is quite clear that the latter underlies the former with 

 an intervening thickness not definitely known, but probably about 10 

 feet. Adding this 10 feet to the combined thickness of the two 

 known sections, the thickness of the dolomitic limestone underlying 

 this part of the village is at least 115 feet, with neither top nor 

 bottom visible. 



Another excellent outcrop occurs in the quarry in the north- 

 eastern portion of the village. This exposure is about 150 feet 

 long (1917) parallel to the strike which is N 50 E. At the north 

 end the dip is W 34, and at the south end W 30. A thickness 

 of 28 feet was measured across the southern end of the quarry, and 

 30 feet across the northern end. The rocks are very distinctly 

 bedded in layers a few inches to 2 feet thick, usually i to 2 feet. 

 Plate 8 gives a good idea of the appearance of the rock in the quarry. 

 Except for a few thin, black shale and sandy shale partings, the 

 rock is all dark gray, fine grained, crystalline, dolomitic limestone 

 very similar to that of the other localities above described. Scat- 

 tering veinlets and bunches of calcite, often dark with organic mat- 

 ter, are common, but no chert was observed. The rock weathers 

 to a light gray. Judging by the strike, dip and location, this quarry 

 section probably lies in part at the horizon of the upper beds of 

 the Rogers brook section, but mostly above it. On this basis, and 

 barring the possibility of an intervening fault, a thickness of some- 

 thing like 20 feet should be added to the thickness above deter- 

 mined for the southern part of the village. This would make the 

 total thickness of dolomitic limestone under the village approxi- 

 mately 135 feet, with neither top nor bottom exposed. 



On the lake' shore one-third of a mile southwest of the mouth 

 of Rogers brook, there are two small exposures of dolomitic lime- 

 stone in beds from 6 inches to I foot thick, with a total thickness 

 of 10 feet. These beds, with strike NT 60 E and dip W 7, are 

 about on a line with, and look much like, the beds at the steamer 



