56 THE CANADIAN NATURALIST. [Vol. X. 



found to contain 3. 808 per cent, silica ; in calculating the results 

 this has been excluded ; the composition of the mineral dried at 

 100® C, then being as follows: 



Phosphoric acid 4G.388 



xVlumina 20.140 



Ferrous oxide 2.091 



Magnesia 13.838 



Lime 2.829 



Water 6.4G8 



100.754 



This is the first tinio that this intercstincr mineral has been 

 met with in Canada. 



a 



WATERS OF THE ASSINIBOIXE ANE RED RIVERS. 



Geological character of the areas drained by these rivers. — The 

 following information in connection with the subject has, at my 

 lequest, been kindly furnished me by Dr. G. M. Dawson. 



'• The Red River, flowing from south to north, runs probably 

 Tor its whole length over deposits of late date. These are, either 

 the fine silty materials laid dowo in the bed of the southward 

 extension of Lake Winnipeg, which previously occupied the valley ; 

 or clays and sand}^ clays due to the glacial period. Long and 

 important streams, however, join the Red River, both from the 

 east and west, and the character of the river water is doubtless 

 due to the nature of the country occupied by the springs and 

 sources of these, rather than to the composition of the bed of the 

 main stream, with which the waters, passing rapidly and in large 

 volume, cannot come very often or intimately in contact. Prob- 

 ably more than half of the water of this river is derived from the 

 Rat, Roseau and Red Luke Rivers and other streams flowing 

 from the wooded and marshy country in the east, and this it may be 

 supposed does not difi'er much from that found in the rivers flow- 

 ing from the woodland country in eastern Canada. This country 

 is also covered with drift deposits of glacial and post-glacial age, 

 and the streams seldom or never flow over solid rock. The tribu- 

 taries from the west including the Shayenne, the Pembina and 

 liumerous smaller rivers, are from a region which may be regarded 

 as almost altogether open prairie, and is subject to a rainfall con- 

 ?:iderably less in amount than that in the east. These streams flow 

 in part over glacial and post-glacial deposits, but in part also 

 over the underlying Cretaceous rocks, of which the shales and 



