138 
gravel, which they strewed broadcast over the southern 
margin of the lake basin, where the bergs stranded and 
melted. The record of this, the iceberg epoch of the glacial 
period, is found in the boulders of Canadian rocks scattered 
over Ohio, Indiana, ete., and often resting upon fine stratified 
clays and sands, which are perfectly undisturbed, and were 
laid down by the same waters across which the bergs drifted. 
This is a state of things which never could occur, unless the 
boulders had been floated down and quietly dropped upon 
their present resting-places. 
Pror. D. 8. Martin, who had announced a paper “‘ On the 
Rhombie Crystallization of Graphite,” said that, as the hour 
was late, he would read the paper in full at the next meeting 
of the section, giving at present only a general summary of 
its contents, with a description of the drawings which he had 
placed upon the board, and of the specimens on the table. 
Graphite has almost invariably been regarded as hexagonal ; 
but he had recently obtained a large number of very perfect 
erystals from Ticonderoga, exhibiting with great distinctness 
a peculiar series of striations, which led him to regard them 
as orthorhombic macles. He dwelt upon the recent deter- 
minations of Prof. J. P. Cooke, in his paper on ‘“‘ The Vermicu- 
lites,” as bearing very closely on this point, and showing 
that much of what has been regarded as hexagonal crys- 
tallization is, or may be, orthorhombic twinning. The hex- 
agonal system is at best an anomaly, in having four axes, 
while there are but three possible dimensions of matter ; and 
it may be, in the light of Prof. Cooke’s researches, that we 
shall be able to dispense with it entirely. If so, the facts 
here presented with respect to graphite, would afford a new 
link in the chain of evidence ; and he desired to put them on 
record now, reserving for another meeting the fuller statement 
of his observations. 
[The strize referred to were pointed out in the specimens, 
and drawn and explained on the board. ] 
Pror. EGLESTON expressed a strong interest in the views 
of the paper, and hoped that it would be presented at the 
first opportunity when there would be time for full and care- 
ful discussion. If true, the discovery was important. 
