128 
The American Geologist. 
February, 1896 
granite quarries near Barre, Vt., and one from the Eustis 
pyrites mine, near Sherbrooke, Que. These outlying dikes 
materially extend the area in which they had been previously 
known. Very curious exposures were also described as hav¬ 
ing been recently uncovered in the Willards Ledge quarries 
at Burlington, Yt. The paper concluded with some reflections 
on the petrology of the dikes. It will appear in full in the 
Transactions of the Academy. 
This paper was followed by one by W. D. Matthew describ¬ 
ing the metamorphism of Triassic coals at Egypt, N. C., by 
the intrusion of diabase dikes. Beginning with samples of 
coal at a distance of 70 feet from the dike it was shown that 
there is a progressive loss of volatile hydro-carbons as the 
igneous rock is approached, and that the bituminous coal 
passes into anthracite and this into prismatic coke next the 
dike. Geological sections and tables of analyses were shown. 
Attention was'called to the fact that similar phenomena have 
been previously described from Virginia, but not from Egypt, 
N. C. The paper will appear in full in the transactions of 
the Academy. 
The last paper was by J. J. Stevenson on “ The Cerrillos 
Coal Fields near Sante Fe, N. M.” Professor Stevenson 
brought out by means of geological sections that there were 
four coal seams contained between two laccolites of trachyte 
which had spread sidewise between the beds for nearly a mile 
from the parent dike or neck> In the topmost seam next the 
neck the coal was a graphitic anthracite passing, as the neck 
was left behind, into true anthracite which graduated into 
semi-bituminous and this into bituminous coking coal. The 
nearness of the laccolites appeared to exercise but little 
influence on the seams that were immediately over or under 
them, but the metamorphic change was due to the dike. The 
middle seam which is at a maximum distance from the two 
laccolites is bituminous coal throughout, so far as known, 
but it has not been worked near the dike. The speaker also 
referred to the change in our former ideas regarding the geo¬ 
logy of the region, in that the intruded rocks have proved to 
be in two separate laccolites, where they were formerly 
thought to be innumerable dikes. The paper was discussed 
by J. F. Kemp, who referred to the fact that the metamorphic 
changes were doubtless due to vapors or heated waters set in 
circulation by the dike, to which the speaker assented. 
J. F. Kemp, Sec’y* 
Gi/acial Lakes of the Boston Basin. 
At the meeting of the Boston Society of Natural History on 
January 1, 1896, Prof. W. O. Crosby and Mr. A. W. Grabau 
read papers showing that the chief deposits of modified drift 
