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The basal beds of the Devonian, which rest upon 

 Silurian limestones northeast of the entrance to Dawson 

 bay, are not known to be exposed about the north end of 

 Lake Winnipegosis. The Devonian section of this region 

 includes two formations, the lower is a dolomitic limestone, 

 estimated to be 200 feet (60 m.) thick, called the Winni- 

 pegosan of middle Devonian age. The upper formation 

 is chiefly a non-magnesian limestone, but it includes some 

 shale, and has a thickness of about 210 feet (64 m.). The 

 younger Devonian formation has been called the Mani- 

 toban. The lower Devonian appears to be absent from 

 this region. The sharp dips of 5 to 20 degrees seen at 

 some localities have only local significance. The general 

 dip of the rocks of this region is westerly and amounts to 

 probably not more than 40 feet ( 12 m.) per mile. 



It follows, therefore, that the outcrops showing only 

 the lower formation of the Devonian lie mainly on the 

 eastern side of the bay. 



A typical exposure of the Winnipegosan dolomite is 

 shown in the cliff at Whiteaves point 10 miles (16 km.) 

 east of the mouth of Steep Rock river. Whiteaves point 

 is a cliff of white compact dolomite with a maximum height 

 of 31 feet (9-4 m.) above the water, and extends a mile 

 along the shore. Beautifully preserved fossils occur in 

 abundance in this dolomite. Among the common and 

 characteristic forms are Stringocephalus burtoni and 

 Gyroceras canadense. The first named species, although 

 a familiar middle Devonian fossil in Europe, is known in 

 America only in the Devonian of Manitoba and Mackenzie 

 River valley. It is nearly everywhere a common fossil in 

 the Winnipegosan dolomite, but does not range upward 

 into the Manitoban formation. Another excellent exposure 

 of the Stringocephalus dolomite occurs at Salt point four 

 miles (6-4 km.) west of Whiteaves point. About 30 feet 

 (9 m.) of white dolomite, weathering yellowish, are exposed 

 in the cliff here. The fauna includes a considerable number 

 of species, among which may be noted Sphaerospongia 

 terssellata, Columnaria disjuncta, Atrypa reticularis, 

 Gypidula comis, Stringocephalus burtoni, Kefersteinia 

 subovata, and Paracyclas antiqua. 



The Manitoban or upper Devonian formation is exposed 

 in several cliffs and points to the north of the mouth of 

 Steep Rock river within a few miles. One of the best 

 sections is exposed at Point Wilkins. Point Wilkins, which 



