BORDERING ON BIG FORK RIVE R. 



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tent to guide us to Fort Francis. Soon after leaving Wa-bush-kon-de-ga, he became 

 bewildered, and acknowledged his inability to direct our course ; and we were there- 

 fore left to our own resources, as on Vermilion Lake. We were detained two days 

 on Rainy Lake ; one, in consequence of being unable to find the outlet, and the 

 other on account of high winds. 



The rocks, which are well displayed on the numerous islands, consist of mica and 

 talcose slates (Nos. 541 and 542), and occasional exposures of granite and gneissoid 

 granite (No. 543). The talcose rocks were met with on the north shore, and the 

 gneissoid granite near the west end of the lake. On an island where we encamped, 

 the mica slate contains innumerable small garnets, and is traversed by granite veins 

 (No. 540), a few inches wide. The tilted edges of the slate are also covered with 

 a crust of coarse granite, of a character similar to that displayed in the numerous 

 intrusions seen on the lower part of Vermilion River. It has every appearance of 

 having been spread over the edges of the mica slate from the veins which traverse 

 it. The slate is very hard and compact, and does not seem to weather with as 

 much facility as the granite. 



From marks observed on Crane, Sand Points, Nemakan, and Rainy Lakes, their 

 waters appear to rise at some seasons to about five feet above their present level. 



We reached Fort Francis on the 9th of September, and were received by Mr. 

 Isbister, the Factor at this post. We remained at this place only long enough to 

 make the portage around the falls, and then started for the mouth of Big Fork 

 River. We were gratified while here by receiving a letter from Dr. Owen, and 

 learning that all his party were well. 



While descending Rainy Lake River, a bed of blue clay was observed, similar to 

 that seen and described on St. Louis and Embarras Rivers. It is full of gravel, and 

 overlaid by a bed of yellow sand. 



7. Big Fork River. — We began to ascend this stream on our way south on the 

 10th of September. It is about sixty yards wide at its junction with Rainy Lake 

 River, but soon grows narrower, and for several miles is not over thirty yards wide ; 

 after which it is increased to forty and fifty yards, which width it maintains up to 

 the mouth of Opimabonowin River. It is very crooked, and winds between banks 

 of clay and sand, from six to twenty feet high for the first twenty-eight miles. The 

 clay-beds are filled with small calcareous gravel and pebbles, as is also the bed of 

 sand. The higher grounds are wooded with small aspen, poplar, birch, bass-wood, 

 ash, spruce, fir, and occasionally a few small pines ; and the river-bottoms with elm 

 and soft maple. Where the woods are open, oak is common, and at one or two 

 places hard maple was seen. 



The clay-beds resemble those already described on St. Louis River, the bluish- 

 coloured bed being also associated here with a dark yellowish one. On the higher 

 grounds the boulder-drift is seen, and associated with the crystalline boulders are a 

 great many large water-worn fragments of drab-coloured limestone, some of them 

 as much as two feet in diameter. Among these fragments Col. Whittlesey found a 

 piece containing several small bivalve shells and remains of Crinoidea. 



About twenty-eight miles above the mouth, the first rock was seen in situ (No. 



