270 The American Geologist. April, 1892 
basin of rocks which may be of Cambrian age. They consist of dark 
argillaceous sandstones with some shaly beds, underlaid by several 
thousand feet of a remarkable volcanic glass breccia, replaced in some 
parts of its course by black slates. The breccia contains light-colored 
angular fragments which, under the microscope are seen to consist of 
silicified pumice, showing, in the most beautiful manner, rows of small 
vesicles as perfect as those in recent volcanic glass. This great band of 
breccia affords conclusive proof of volcanic action on a grand scale in 
these early geological times. At the base of the series is a band of 
quartzite-conglomerate with white quartz pebbles. 
The celebrated nickel and copper deposits of the Sudbury district 
come within this area and are described by Dr. Bell. He gives the re- 
sults of his investigations on the relations and mode of occurrence of 
these ores. They would appear to be always associated with the green- 
stones, and to be most abundant at the contact of these rocks with some 
other, especially where the contact is intersected by a line of dislocation 
or by one of the gabbro dykes, which are numerous in the district. The 
occurrence of gold, silver, lead and other metals is described, and assays 
for nickel and gold are given by the chemists of the survey. 
There are four appendices: I contains a careful description of the 
microscopic and other characters of about fifty kinds of rocks from the 
district by Prof. Geo. H. Williams, of Johns Hopkins University. 
II gives the levels along the Canadian Pacific Railway and of the prin- 
cipal lakes. II] isa list by the best authorities of 73 species of Lepid- 
optera, collected by Dr. Bell north of lake Huron, and IV explains the 
meanings of the Indian geographical names in the surrounding country. 
The report is illustrated by some fine photo-engravings. 
LIST .OF RECENT PUBLICATION: 
IT. Proceedings of Sctentifie Societies. 
Trans. N. Y. Acad. Sci. Nov.-Dec., contains: On the Geological Age 
und Relations of the Potomac Group of Virginia and Maryland, J. 58. 
Newberry; On the Microbe of Phosphorescent Wood, A. A. Julien; 
Note on Hydrazoic Acid, a new mineral acid, H. C. Bolton. Jan-Feb. 
Vo. contains: —Monticellite, anew mineral, J. F. Williams; Recent Work 
in North American Mammalogy, J. A. Allen. March No. contains:— 
Man of the Stone Age, F. Starr. 
Trans. Canadian Inst., Oct., 1891, contains: Notes on Nickel, by George 
Mickle; Bone-Caves, by Arthur Harvey; Gold and Silver in Galena and 
Iron Pyrites, by R. Dewar. 
Jour. Elisha Mitchell Scient. Soc. for 1891, Part I., contains: The Alex- 
ander Co. Meteoric Iron, 8. C. H. Bailey. 
Proc. Calif. Acad. Sci. Vol, III, Part 1, contains: Notes on the Geology 
and Petrography of Baja California, Mexico, Waldemar Lindgren; 
