368 



is four miles (6-4 km.) north of Steep Rock river, rises 80 

 feet (24 m.) above the lake. The cliffs here expose the 

 following beds of the Manitoban formation: — 



b. Light grey, fine grained, thin-bedded limestone, 

 some beds breaking with conchoidal fracture, 45 ft. (13 • 7 m.) 



a. Light ash grey, argillaceous limestone 35 ft. (10 -6m.) 



The species which are most abundant in the lower beds 

 (b) are Atrypa reticularis and Paracyclas elliptica. The 

 upper beds contain a very sparse fauna, in which Athyris 

 vitata is one of the most abundant species. Stringocephalus 

 burtoni and many of the other fossils of the Winnipegosan 

 dolomite are unknown in this upper formation. 



An interesting feature of the Point Wilkins section is the 

 brecciated beds which appear very near the southern end 

 of the cliff. Here, where the cliff has a height of only about 

 25 feet (7-6 m.), the horizontal and undisturbed limestones 

 pass abruptly into a belt of limestone which has been 

 broken into large angular blocks; these have been more or 

 less completely recemented together. Some of the inter- 

 spaces are filled with a light grey micaceous sandstone. 

 There are no Devonian beds in any part of the section 

 which resemble this sandstone filling. It probably repre- 

 sents material which sifted into the interstices of the 

 breccia during the deposition of the Dakota formation of 

 the Cretaceous, which further westward overlies the 

 Devonian limestone. 



Immediately south of the Point Wilkins cliffs, and a few 

 rods from the brecciated limestone an old forest-covered 

 beach of comparatively recent date rises about 15 feet 

 (4-5 m.) above the surface of the lake. Another and much 

 older beach or bar 6 to 8 feet (1 -8 to 2-4 m.) high extends 

 across the top of the cliff 100 to 200 yards (91 to 182 m.) back 

 of its face. This beach stands about 85 feet (26 m.) above 

 the level of the lake. The present high stage of the lake is 

 indicated by the line of dead birches now standing on the 

 edge of the lake along the foot of the Point Wilkins cliff 

 on the northeast side. 



Numerous salt springs issue from the Devonian limestone 

 at various points along the streams entering the west side 

 of Dawson bay. North of the mouth of Bell river, two 

 and three quarter miles (4 -4 km.), a small brook enters 

 the lake which is estimated to discharge into the lake 

 37^ tons of salt every 24 hours [4.]. The salt beds thus 

 indicated in the Devonian are known only through the 

 saline springs. 



