Review of Recent Geological Literature. 261 
theories of coral reefs ; geologic causes of the present distribution of 
animals and plants; mineral veins, faults, and mountain-building; De- 
vonian fishes, and Carboniferous conifers; the origin of birds and mam- 
mals ; the Potomac, Comanche, and Laramie series ; the Tertiary mam- 
malian fauna of America ; evidences of continental elevation during 
the Quaternary era, regarded as the probable cause of the glacial 
climate ; the Quaternary upheaval of the Sierra Nevada and Great 
Basin ranges ; terminal moraines and ice-dammed lakes ; and the most 
recent discoveries of human remains and implements, both in Europe 
and on this continent. 
A last word with the Huronian. By Alexander Winoiiell. Bulle- 
tin of the Geological Society of America, vol. ii, pp. 85-124, with a map 
and three figures in the text; Feb. 5, 1891. Only two weeks before the 
death of its distinguished author, this brochure was issued ; and in the 
March number of the Geologist ( p. 199 ) his discussion of the progress 
of opinions held by American geologists concerning the Taconic and 
Archaean rocks was noticed. Little did Dr". Winchell expect that liter- 
ally this essay would be his last utterance in the science which he had 
done so much to advance ! He was looking forward to the preparation 
of an elaborate treatise on the ancient metamorphic rocks of the North- 
west, toward which these recent publications were as stepping-stones. 
The diverse uses of the name Huronian by Murray, Logan, Hunt, Irving 
and others, are stated, with comparisons of the areas where rocks re- 
ferred to this system are developed north of lake Huron and about lake 
Superior ; and the author adds notes of his personal observations in the 
vicinity of Echo lake, 15 miles east of Sault St. Marie. It is advocated 
that the name Huronian be retained for the quartzites, schists, and 
slate conglomerate, to which it was originally applied, unless it should 
be superseded by Taconic as an earlier synonymous name ; but that a 
lower series of schists, conglomerates, and slates, to which the name 
Huronian has been extended, be distinguished as the Kewatian system, 
following Lawson's classification, which is based on explorations about 
the Lake of the Woods. 
The Nickel and Copper deposits of Sudbury district, Canada. By 
Robert Bell. With an appendix on The slicifled glass-breccia of Ver- 
milion river, Sudbury district, by George H. Williams. Bulletin, G. S. 
A., vol. ii, pp. 124-140, with four figures in the text ; Feb. 5, 1891. The 
recently discovered ores in the region about Sudbury, a station of the 
Canadian Pacific railway north of lake Huron, arc in all cases a mixture 
chalcopyrite and nickeliferous pyrrhotite. They arc found upon a tract 
about 7() miles long from southwest to northeast, with a maximum width 
of about 50 miles, occurring principally along fault-planes of diorite as a. 
matrixof igneous injection between its brecciated fragments. Nickel is 
confined to the pyrrhotite. in which it is usually present in the proportion 
of from 1 to 5 per cent. A remarkable volcanic glass-breccia of great 
thickness and extent, whose structure has been perfectly preserved by 
si lici fixation, is closely associated with the diorite. 
