Personal (ind Sclentijic Neics. 63 
iug north, and the marble quarries in the Green mountains and Berk- 
shire hills, coming south. His remarks 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, near Mj^stie, Conn. 
The .speaker described the vein as about 400 ft. in width and at least 
1,200 ft. in length. Its northern extremity forms the summit of Lan- 
tern hill about 500 ft. 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 loose, 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 Vjetvveen the fingers and is easily dug with pick and shovel 
without any blasting. 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 SiO., . A few rare scales of 
some migaceous or chloritic mineral are practically the only other ones 
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, although he inferred on the spot the 
action of some corroding alkaline solution, presumably magnesian. The 
paper was discussed by Messrs. Dodge and Hovej'. 
The third paper of tlie evening was b}^ J. F. Kemp and was 
entitled "The Pre-Cambrian Topography of the Adirondacks." 
The speaker mentioned the curious outliers of Cambrian and Ordovi- 
cian strata that have been discovered far un in the mountains from the 
main outcrops that skirt them. They lie in valleys in metamorphosed 
crystalline rocks, which valleys represent beyond question the old pre- 
Cambrian river valleys and which were filled with sediment by the en- 
croaching sea of Cambrian and Ordovician time. Lake George is the 
largest example of this kind and contains remnants of Potsdam sand- 
stone and Trenton limestone in its southern portion. The valley of 
Trout brook, which lies just west of Rogers rock at the north end of 
lake George and is separated from it by a high intervening ridge of 
gneiss, contains two outliers of Potsdam sandstone of a few acres in ex- 
tent. In the valley of Putnam's jjond in the western part of Ticonder- 
oga township there is another outlier of Potsdam sandstone. Both of 
these are shown on the map of Ticonderoga which accompanied the 
speaker's report to Prof. James Hall on this region, pviblished in 1895. 
Another isolated area of Calciferous limestone, is found on Schroon 
lake, under Schroon Lake post office. It is a few acres in extent and 
the exposed rock is about 75 ft. thick. It is 850 ft. above tide at its 
upper point. Down the lake and river valley it is nearly forty miles to 
the next Cambrian outcrop, which is below Hadley. The speaker also 
cited the little outlier of Trenton limestone near Wells on the Sacon- 
daga river and the fact that the CamV:)rian and Ordovician sediments 
on the west side reach short distances into the areas of the crystalline 
rocks along the river valleys. He stated that all the outliers on the east 
side had a uniform northeasterly strike and a dip of 10 to 20 degrees to 
the northwest. He remarked that they occurred in the valleys of 
streams which are notably sluggish, explaining their slow movement by 
the fact that they flow in pre-Caml)rian valleys, already nearly reduced 
