230 Tlic America}! Geologist. October, i898 
Still, the chief and most marked optic character distin- 
guishing this mineral from thomsonite is its much lower 
double refraction. This mineral never shows colors, between 
crossed nicols, in a section of ordinary thinness for micro- 
scopical purposes, even when cut parallel to the optic plane, 
while thomsonite uniformly rises into red, and to blue of the 
second order, in sections of .03 mm thickness. 
Localities. The most celebrated localities are at Terrace 
Point, which encloses Good Harbor bay, a few miles west of 
Grand Marais, and thence westward to Poplar river. It is 
frequently seen as waterworn pebbles in the gravel of the 
beach. It occurs at Lover's bay, at Gooseberr}' River falls, 
at Pork bay, Beaver bay and Agate bay. It is evidently a 
product of alteration of labradorite in the coarse diabases 
and gabbros. As such it occurs plainly at the cast point of 
.Sucker bay (90B) where it results from a change in labra- 
dorite. The most remarkable instances of such alteration 
occur at Carlton's peak, as discovered by Mr. A. H. Elftman. 
Here the anorthosyte holds nests of radiated fibres of meso- 
lite as large as two or three inches in diameter. 
[European anrl American Glacial Geology Compared, IX.] 
GLACIAL RIVERS AND LAKES IN SWEDEN. 
By Waeeen Upham, St. Paul, Minn. 
Among the several European countries through which our 
travel last year extended, none was geologically more interest- 
ing to me than Sweden, because it affords very instructive 
comparisons with my earliest and latest geologic studies in 
America, first, on the origin of kames and eskers in New 
Hampshire,* and, last, on the glacial lake Agassiz,t in the 
basin of the present lake Winnipeg. In the same year (1876) 
*Proc. A. A. A. S., XXV, for 1876. pp. 216-225. Geology of N. H. 
vol. Ill, 1878. 
tGeol. and Nat. Hist. Survey of Minnesota, Eighth Annual Report, 
for 1879, pp. 84-90; Eleventh Rep., for 1882, pp. 137-153. with map; 
Final Report, vols. I (1884) and II (1888). Geol. Survey of Canada. 
Annual Report, nevv^ series, vol. IV, for 1888-89, Part E, 156 pp. with 
maps and sections. U. S. Geol. Survey, Monograph XXV, 1896, 658 
pp., with 38 plates and 35 figures in the text. 
