1896. ] NEW YORK ACADEMY OF SCIENCES. 189 
were copiously illustrated by the lantern and by many beautiful 
specimens. The paper was discussed by Messrs. Martin, Dodge 
and Kemp, to whose remarks the speaker replied. 
' The second paper of the evening was by J. F. Kemp, on “ The 
Great Quartz Vein at Lantern Hill, Mystic, Conn., and its De- 
composition.” The speaker described the vein as being about 
400 feet in width and at least 1,200 feet in length. Its northern 
extremity forms the summit of Lantern Hill, about 500 feet 
above sea level. This portion is of hard milky white quartz. 
The southern extension of the vein forms Long Hill. It is 
lower in altitude and largely composed of less pulverulent 
quartz, which, however, perfectly preserves the comby structure 
of the quartz vein. It consists of innumerable interlocking 
masses of quartz crystals. It is but slightly iron-stained in a 
few spots. It is so soft that it can be crumbled between the 
fingers, and is easily dug with pick and shovel without any blast- 
ing. The vein strikes north about 15 degrees east and cuts 
squarely across the laminations of the gneiss. It is one of the 
largest quartz veins known in the East and is of very pure 
silica. Samples from the crumbly portion range from 98 to 99.4 
per cent.of SiO,. <A few rare scales of some micaceous or chloritic 
mineral are practically the only other materials present. Under 
the microscope the powdered quartz appears quite fresh, and 
exercises a vigorous influence on polarized light. Some prism 
faces of quartz crystals show etched figures, but in general the 
evidence of corroding alkaline solutions is hard to find. The 
speaker was therefore led to refer the pulverulent character of 
the vein to the effects of a faulting or crushing movement, al- 
though on the spot he inferred the action of some corroding 
alkaline solution, presumably magnesian. The paper was dis- 
cussed by Messrs. Dodge and Hovey. 
The third paper of the evening was by J. F. Kemp, and was 
entitled: ‘The Pre-Cambrian Topography of the Adirondacks.” 
The speaker mentioned the curious outliers of Cambrian and 
Ordovician strata that had been discovered far up in the moun- 
tains at long distances from the main outcrops that skirt the 
mountains at lower levels. The strata lie in valleys in the 
