1882 .] 
343 
[Davis. 
and still more surely to North America. The observations of 
Hector 1 and Logan , 2 accepted by Ramsay 3 to prove that the lakes 
of Canada and British America lie in rock-basins, are insuffi- 
cient, as attention was not given especially to this point ; the 
region is one of difficult exploration, and the frequent mention of 
drift by its explorers 4 shows how much effect may be traced to 
barriers when it is more studied. 
Small mountain tarns of glacial origin 8 are common in the 
higher ranges of the world, but they are so generally due in part 
to morainal obstruction that it is difficult to select many examples 
coming fully under this species. In the Alps, there are small 
rock-basins, as at the Grimsel Hospice, and on the summits of many 
passes . 6 Coom Keagh, in a “corry” or rock hollow, and some 
others, are given as examples for Ireland , 7 but true rock-basins 
“ seem to be much rarer than has been supposed,” for the lakes there 
are most frequently dammed in by loose rocks, gravel and clay. 
In New Hampshire and Maine, rock-basins are observed 8 but gen- 
erally a drift-barrier contributes generously to the production 
1 Geogr. Soc. .Tourn., xxx, 1860, 268 ; Geol. Soc. Journ. xvu, 1861, 388. 
2 Geology of Canada, 1863, 6, 889. 
3 Geol. Soc. Journ., xvm, 1862, 201. 
4 See the later reports of the Canadian Geol. Survey. Many of the smaller lakes in 
the region of crystalline rocks are said to occupy shallow rock-basins. G. M. Dawson, 
Geol. and Resources of the 49th Parallel, 1875, 22, 245. 
5 E. Hull suggests that tarn be limited to small lakes of glacial origin. On the Ves- 
tiges of Extinct Glaciers in Cumberland and Westmoreland. Edinb. Phil. Journ., 
xi, 1860, 31-44. See also Ward, Pop. Sci. Review, 1879. 
6 Bonnev, Lakes of the Northeastern Alps and their bearing on the Glacial erosion 
Theory, Geol. See Journ., xxix, 1873, 382 ; also, xxx, 1874, 479. Viollet-le-Duc, Les 
Lacs Superieurs, Club Alpin Franty Ann. i, 1874, 277-282. A. Boud considered 
some of these high lakes of violent plutonic origin, but gave .no good proof of his 
view. Die Seen- utrd Teichbildung, Wien Akad. Sitzungsb., xliv, 1861, 1°, 621- 
628. 
7 M. H. Close, On some Corries and their Rock-Basins in Kerry, Ireland, Geol. Soc. 
Journ., ii. 1870, 236. G. H. Kinahan in chapters on the “Lake Basins of Iarconnaught ” 
and the “ Valleys of some of the Irish Lakes," in his work on Valleys states that drift bar- 
riers hold back many of the lakes but considers some as true ice-worn rock-basins ; his 
observations are not given with sufficient detail to allow one to judge of their accuracy. 
3 C. H. Hitchcock, Geol. N. II., in, 1878, 250. Professor Hitchcock writes me that he 
considers Memphremagog and Connecticut Lakes in N. II., and Moosehead in Maine, as 
rock-basins 
