3 66 



thickness of about 12 feet (3-6 m.) is exposed. These 

 beds seem to be similar to those shown in the upper half 

 of the 16 foot (4-8 m.) cliff on the north end of the island. 



Other outcrops of the rocks here described are to be seen 

 on the south shore of Lake Winnipegosis adjacent to the 

 island. As may be noticed on the map one of these is 

 directly west, and the others directly south of the south end 

 of the island. 



None of these exposures exhibit any features not shown 

 at that place, with the exception perhaps of those imme- 

 diately south which may contain more fish remains than 

 the outcrops on Snake island. These remains are probably 

 of Dinichthys canadensis mentioned by Tyrrell in his report 

 on the island. [4 p. 163.] 



The vicinity of Winnipegosis and Snake island is par- 

 ticularly interesting from the standpoint of the develop- 

 ment of the knowledge of Western geology for "It was 

 here that Prof. H.Y. Hind [1.] in 1858 made the collection 

 of fossils which first determined the existence of Devonian 

 in Manitoba." [4 p. 163]. In the same year a report was 

 made on the occurrence of rock on the island by A. W. 

 Wells [2.]. In the summer of 1889, the island was visited 

 and reported on by Tyrrell [4.], from whose report the 

 references just cited have been taken. 



THE DEVONIAN OF DAWSON BAY, LAKE 

 WINNIPEGOSIS.^ 



Dawson bay is a large pocket-like expansion extending 

 west and south from the northern end of Lake Winni- 

 pegosis. This bay is excavated wholly in Devonian rocks 

 and the numerous exposures on its islands and shores and 

 along Red Deer river show the whole of the Devonian section 

 so far as it is known. This makes Dawson bay the most 

 favourable region in which to study the Devonian section 

 of Manitoba. 



A spur leaving the main line of the Canadian Northern at 

 Mafeking reaches the bay at the mouth of Steep Rock 

 river. From this point the localities to be mentioned will 

 be reached by gasoline launches. 



a This excursion is contingent on the completion of the branch railway from 

 af eking to the mouth of Steep Rock river. 



