4I 
(1894) and exhibited by J. F. Kemp. The geology and min- 
eralogy are practically the same as at Sudbury, Ont. The Gap 
Mine began to produce nickel about 1862, and for twenty years 
was the principal nickel mine of the world. 
(Ten specimens.) 
186. Collection of ORES, COUNTRY ROCK, AND PHOTOGRAPHS, 
from the Mesabi Iron Range, of Minnesota. Collected (1894) and 
exhibited by J. F. Kemp and T. G. White. The Mesabi ores 
have almost revolutionized iron mining on Lake Superior. 
Enormous bodies of soft but rich ore lie under a cap of gravel 
and in cherts and quartzites. The photographs exhibit the 
methods of mining with steam shovels. 
(Twenty-five specimens.) 
187. Collection of PRE-CAMBRIAN VOLCANIC ROCKS, from various 
points on the Atlantic seaboard, including St. John, N.B., Mt. 
Desert and Mt. Kineo, Me., Marblehead and Quincy, Mass., the 
South Mountain, Pa., and Southwest Virginia. Collected and 
exhibited by W. D. Matthew, T. G. White, and J. F. Kemp. 
It is now known that just before the opening of the Cambrian 
period, volcanic action was widespread along the Atlantic sea- 
board. The old acidic lavas, tuffs, etc., have been usually called 
felsites, but they have been found to possess, in greater or less 
perfection, all the characteristic structures of recent lavas. The 
New Brunswick and Mt. Desert collections are to be described 
before the Academy. 
(Thirty specimens.) 
188. SLABS OF FOSSILIFEROUS SHALE, SHOWING THE EFFECTS 
OF LATERAL COMPRESSION. Upper Devonian, Ithaca, N. Y. 
Collected and exhibited by Gilbert van Ingen. The slabs are 
marked with north and south lines. The force which distorted 
the fossils was applied in an approximately north and south 
direction, which is perpendicular to the axes of the anticlinal 
and synclinal folds that cross the lake region of Central New 
York. The evidence suggests that the distortion of the fossils 
and the formation of the folds were produced by the same 
force acting at the same time. Exhibited by Gilbert van 
Ingen. 
