ASSOCIATION OF AMERICAN GEOLOGISTS. 37 
widely separated localities^ as tliat evidenced in the course of the 
glaciers alluded to. 
In the evening Prof. Silliman delivered a most interesting ad- 
dress on the "Progress of Geological Science in the United 
States.'' 
April 27th, 1842. — Dr, Morton in the chair. The conside- 
ration of the Drift/' question was adjourned to the next ses- 
sion. The objections to the views presented by geologists, are 
1st, the washing up of ridges along the shores of lakes ; 2ndly, 
those of glaciers ; 3rdly, those of icebergs ; 4thly, alluvial beds ; 
5thly, the accumulation of boulders along what were ancient 
coasts ; 6thly and 7thly, pot holes and slickensides. 
April 28th, 1842.— Prof. Silliman in the chair. Dr. C. T. 
Jackson read a paper " On the Tin Veins of New Hampshire/' 
exhibiting specimens of ore both crystallized and compact, and 
an ingot weighing three ounces of the reduced metal, obtained 
from five ounces of the ore, the accompanying minerals of the 
veins at Jackson, also specimens of the yellow blende of Eaton 
and the black blende of Shelburne, with a specimen of the asso- 
ciated lead ore. 
Prof. W. B. Rogers adverted to the occurrence of oxide of tin 
in Yirginia, associated with auriferous quartz and other mine- 
rals of some of the gold mines — he had found it but rarely, and 
then in the talco-micaceous slate, near its junction with the au- 
riferous quartz. He also remarked that he had found the sul- 
phuret of zinc sometimes, and the silicate (electric-calamine) 
very abundantly in the lead mines of Wythe Co. Virginia. The 
latter often occupies the greater part of the breadth of the vein, 
whilst the sulphuret is met with in nests and thin veins, in the 
sparry and magnesian limestone adjoining the lead ore. The 
same mines yield large quantities of beautifully crystallized 
white carbonate of lead, and a considerable quantity of the red 
oxide (native minium), and the yellow oxide has also been found 
there. 
