te) 
clay. The zinc blend has yielded calamine, a hydrated 
silicate of zinc, that has leached down and formed incrus- 
tations on the undecomposed limestone. 
These mines were described to the Academy Novem- 
ber 18, 1895. 
3. Suite of SpecrmENs from Essex County, N. Y., showing the 
development of crushed and brecciated rocks and gneisses 
from. originally massive igneous forms. Exhibited by 
Prof. J. F. Kemp. The specimens are the labradorite 
rock and gabbros from the Adirondacks. No. 1 shows a 
massive, coarsely crystalline aggregate of dark crystals of 
labradorite from Lake Sanford; in No. 2 and following 
numbers the minerals are more and more crushed until 
only a pulp of the original rock is left in No. 13. Nos. 
14-19 show the development of gneissoid forms; Nos. 20 
and following exhibit the passage of massive gabbro into 
hornblende gneiss. The changes were brought about by 
dynamic metamorphism. 
4. Series of Rock SpEcIMENS, Maps and Puotrocrapus illus- 
trating the geology of Mount Desert Island, Maine, and 
vicinity. Exhibited by Theodore G. White, Geological 
Department, Columbia University. 
This embraces the original metamorphosed, unfossil- 
iferous slates, through which the following rocks were 
ejected: The red granite, forming the central core of the: 
island; rhyolites, varying in type and structure; repre- 
sentatives of a few of the dikes; ores and associated rocks 
from the Blue Hill and Cape Rosier, Maine, copper 
mines; contorted quartzose schists from Blue Hill. 
5. Set of Rocks from the southern portion of the Boston Basin, 
Mass., collected by Prof. W. O. Crosby. Exhibited by 
Theodore G. White. 
This series embraces the Paradoxzdes slates of Brain- 
tree; the Quincy hornblendic granite; biotitic granite ; 
diorites and dioritic granites; flow and_ porphyritic’ 
