No. I] GEOGNOSTICAL OBSERVATIONS. 505 



It is only a few yards long, and separates the Echemamis, a rivulet tributary 

 to the Nelson, from one of the sources of Hayes' River. 



The Echemamis flows, or rather filters, through a swamp for thirty miles ; 

 when, having previously formed a slight expansion termed Hairy Lake, and 

 assumed the name of Blackwater Creek, it terminates in Sea River, one of the 

 arms of the Nelson. This swampy district is traversed by many round- 

 backed ridges of gneiss, having a direction from east to west, and rising to 

 the height of one hundred and fifty feet. Several beds of hornblende slate are 

 enclosed in the gneiss. On Sea River, and in Play-Green Lake, the same rocks 

 were observed. At Sea River Carrying-Place, a granitic gneiss forms a round- 

 backed low ridge, running nearly east and west. It contains some small 

 beds of porphyritic red granite, in which there are included some masses of 

 mica slate ; the slate penetrating and intimately mixing with the granite at 

 the line of junction. In Play-Green Lake the gneiss forms many low smooth 

 round-backed islands. 



The primitive rocks disappear under the clay, below Norway Point. The 

 north shore of Lake Winipeg is formed into a peninsula by Play -Green Lake 

 and Limestone Bay. It consists of steep clay cliffs, similar to those which pre- 

 ceded the gneiss in Hill River, but containing rather more calcareous matter. 

 When the lake is low, there is a flat beach betwixt it and these cliffs ; but in 

 southerly winds the waves wash their bases. The beach is composed of a 

 fine calcareous sand, and small fragments of water-worn limestone. The 

 same materials form a narrow bank, which running to the S.W. for about 

 eight miles, separates Limestone Bay from the body of the lake. The frag- 

 ments belong to two kinds of limestone ; the one yellowish white and dull 

 with a conchoidal fracture, and translucent edges ; the other bluish and 

 yellowish grey, dull, with an earthy fracture and opaque. 



We did not observe any rocks of the former kind in situ in this neighbour- 

 hood* ; but cliffs of the latter appear on the west side of Limestone Bay, 

 and continue to bound the lake as far as the mouth of the Saskatchawan, and 

 as we have been informed, down the whole of its western shore. 



This limestone, which extends over a vast tract of country, probably belongs 

 to the great series of limestone formations under the green sand, and above the 



* 



*A similar rock, however, was found in Pine Island Lake, fifteen miles N.N.E. of Cumberland-House 



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