

No. L] GEOGNOST1CAL OBSERVATIONS. 517 



grey vitreous looking quartz. In a bay of the lake, about a mile farther to 

 the eastward, there is a cliff of clay slate. On leaving Fort Chipewyan, we 

 paddled through several miles of lake, and then descended the Stony River. 

 Rocks, similar to those in Athabasca Lake, but possessing less elevation, rise 

 above the swampy borders of this stream. At the distance of eighteen miles 

 from Fort Chipewyan, it falls into the Peace River, when the united streams 

 assume the name of Slave River. 



The most abundant rock on the Slave River is granite. A red granite occurs 

 opposite to the portage into Duck Lake. Near a point termed the Bute, the rocks, 

 comprised of felspar, quartz, and chlorite, have a slaty structure. Below this, the 

 granite rising in the channel of the river forms the Carreboeuf Islands. A rock, 

 examined opposite these islands, was composed of felspar and quartz, probably a 

 variety of granite. Lower down, the ridges of granite rise higher and prove a 

 more formidable obstruction to the river, producing many cascades and rapids. 

 At the Cassette Portage, a bed of mica slate, composed of grey quartz and mica, 

 occurs in the granite. At the Little Rock Portage below the Portage d'Embarras, 

 a rock, composed of felspar quartz and chlorite, occurs. It is similar to that 

 observed at the Bute above-mentioned, but wants the slaty structure. It is 

 the protogine of Jurine. At the upper end of Mountain Portage, the same 

 chloritic, granite, or protogine, again occurs in large quantity. In the middle 

 of the portage, a variety of this rock occurs, composed principally of quartz, 

 with a little chlorite and felspar ; and adjoining to this bed there is another, 

 composed of red felspar and grey quartz. The protogine succeeding again 

 forms the lower and principal part of the portage. At the Hauling Place 

 below the Mountain Portage, a variety of granite which has been just men- 

 tioned as composed of red felspar and grey quartz again occurs, and alter- 



? 



nates with the protogine both there, at the Pelican Fall, and at the Portage des 

 Noyes. The granite disappears about a mile and a half below the latter 

 portage, and the banks of the river from thence to Slave Lake are alluvial. 



The Salt River flows in from the westward a short way below the portages. 

 We ascended it for twenty-two miles, including its windings, but not above 

 half that distance in a straight line, for the purpose of visiting the salt springs 

 from whence it derives its taste and name. Seven or eight copious saline 

 springs issue from the base of a long even ridge about six hundred feet high, and 

 spreading their waters over an extensive clayey plain, deposit a considerable 

 quantity of very pure common salt in large cubical crystals. The mother 



