REPORT OF THE CHIEF ASTRONOMER 33 



SESSIONAL PAPER No. 25a 



map all the area enclosed between the International line and the Kootenay 

 river as it swings through the great bend between Gateway and Porthill is 

 shown as occupied by the ' Loop mountains.' That subdivision lying to the 

 west of the Moyie river is mapped as the ' Moyie range ' ; a middle subdivision 

 lying between the Moyie river and the Yahk river is mapped as the 'Yaak 

 range ' ; an eastern division, lying to the eastward of the Tahk river is mapped 

 as the ' Purcell range.' 



No discussion of this scheme of nomenclature is given in MaeDonald's 

 paper, which was apparently written about the time when the preliminary 

 paper of the present writer was in preparation. The name for the eastern 

 subdivision of the Loop mountains was evidently given in the belief that the 

 local Purcell range, as mapped by Palliser and Dawson, should be extended 

 southward across the Boundary. A serious objection to this proposal is that 

 the unit mapped by Palliser as the ' Purcell range ' is, at the south, cut sharply 

 off by the strong transverse valley of St. Mary river and by the wide plains 

 about Cranbrook, nearly forty miles north of the Boundary line. If, then, 

 it were thought expedient to limit the name ' Purcell ' to an elementary range 

 unit, as suggested though not enforced in Palliser's map, it is hardly possible 

 to carry the Purcell range south of St. Mary river. On the other hand, we 

 have seen that some official usage and the usage of several influential atlases 

 have familiarized us with the idea of giving the old name ' Purcell range ' to 

 the entire mountain group occupying the area between the Rocky Mountain 

 Trench and the Purcell Trench. This view implies that the rangelet limited 

 on the east by the local mountain wall seen by Palliser as he looked across 

 the Rocky Mountain Trench and mapped as belonging to the ' Purcell range,' 

 shoidd receive a special definition and a special name as soon as its extent 

 as an orographic individual is known through actual mapping. 



The general name ' Loop mountains ' was presumably suggested by the 

 loop of the Kootenay river, which bounds the whole group on the south. This 

 great bend in the river is so remarkable a feature that the name is certainly 

 appropriate on the United States side of the Boundary line. It is, however, 

 true that four-fifths of the area and five-sixths of the length of the orographic 

 unit involved, lie to the north of the Boundary and in no immediate relation 

 to the bend of the Kootenay. For the greater part of the unit the name ' Loop 

 mountains ' is not appropriate. It is clear that the political boundary should, 

 ideally, have no influence in fixing the general name. Systematic orography, 

 supplemented by priority of usage, seem to declare for the older general name 

 4 Purcell range ' for the mountains considered, whether north or south of the 

 line.* 



In summary, then, the great range unit here called the Purcell range is 

 bounded by the Rocky Mountain Trench, the Purcell Trench, and the portion 

 of the Kootenay valley stretching from Jennings, Montana, to Bonner's Ferry, 

 Idaho. 



* Since the last paragraphs were written, Calkins has published Bulletin 384 of the 

 United States Geological Survey, in which (Plate I) the "Loop mountains" are re-named 

 the "Purcell mountains/'' 

 25a— 3 



