Geology and Mineralogy. 151 
chemical examination of materials obtained from several “‘ Forts 
vitrifiés” in ee parts of France. This name is given to the 
walls or to the simple debris of walls, whose materials have been 
fused together by the action of fire. 
The substance obtained from the neighborhood of Argentan 
was of a dark greenish brown color, opaque, and resembled 
When sections of the nite were examined in the microscope 
it was found that the ive belees still acted upon polarized light, and 
the albite also was many assess. but erate them there were 
vitreous masses produ yt Of the minerals formed 
the process, spinel ery mon in sae i octahedrons, 
sometimes transparent, sometimes opaque. There are also large 
umbers of microlites in eodes ii — d mica, which 
Mating played an important part in accompan yin 
the aaa These granites had been fused aa by fire 
without aid of soda, the first med, and it is 
‘impisiae certain that the process of na together the small 
agments was intentional although the means ey which it was 
paeiory earho so thoroughly is less easy to understand. 
ce L Outlet of the Basin of Lake Erie into that of 
Lake Ontario,—Mr. . SPENCER discusses this subject in a 
paper published 3 in the Proceedings of the American Philosophical 
Society for 1881, He reaches the conclusion that a deep channel 
passed off from the southern part of Lake Huron along the course 
. eirgaieg ste of the Au Sable, pursued an east-southeast 
ourse and d the basin of Lake Erie west of Vienna, bent 
around Tong pe tc east of Vienna), and then took a north-by- 
west e to Ancaster in the Province of Canada, whence it fol- 
3. 
to ow et was Skew he es owe their na Ts to saariedair and 
Am. Jour. Sor, ; Sertns, Vor. XXH, No. 128,—Avueust, 1881. 
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