55% APPENDIX. 



portion of the north-east of Great Slave Lake, — includ- 

 ing the long island of Peth-the-nu-eh, and one, at least, 

 of the smaller islands adjacent to it, which Captain 

 Back describes as composed of trap rocks, but which 

 include also strata of limestone. 2. — Perhaps, the 

 rugged ground about Lake Beechey ? which, from the 

 description, appears to differ much in aspect from the 

 primitive country. 3. — Limestone is mentioned in the 

 narrative, as having been found in small fragments, on 

 the shore of Montreal island, in the estuary of the 

 Thlew-ee-choh-dezeth. * 



On a general view of the map of Captain Back's late 

 expedition, it may be remarked that the river is obvi- 

 ously divided into three portions (and the eastern part of 

 Slave Lake itself may perhaps be considered as resem- 

 bling them), all nearly parallel, and lying in a direction 

 from about south-west to north-east, allowance being 

 made for the convergence of the meridians in those high 

 latitudes. These portions are : 1 . — The Thlew-ee-choh- 

 dezeth, from its source in Sussex Lake, to the head or 

 north-western extremity of Lake Beechey. 2. — From 

 the curve a little eastward of Baillie's River, to the north- 

 western extremity of Lake Pelly. 3. — From Wolf 

 Fall, — and, more distinctly, from the rapids north of 

 Mount Meadowbank, to the sea. 4. — Slave Lake itself, 

 from the entrance of Slave River to Fort Reliance, — 

 and the river which connects it with Artillery Lake. 

 The first of these divisions being about eighty-five En- 

 glish miles in length; the second, nearly an hundred 



* Instead of this unwieldy name for the newly discovered 

 stream, that of "Back's River" has been suggested; the 

 most appropriate denomination, in such a case, being that of 

 the discoverer. 



