me Postscript. 
proved, and I will immediately cause a resurvey of the state to be 
made by other scientific gentlemen. 
S. Van RenssEarr. 
Albany, June 22d, 1831. 
Remarks.—Although we have not always agreed in opinion with 
our correspondents, and with Prof. Eaton among the rest, we have 
been satisfied that his valuable labors have contributed very materially 
to the advancement of geological knowledge in this country, by pro- 
moting investigation, and adding largely to the mass of facts, which 
constitute the true riches of geology. Were the entire crust of the | 
planet fully explored, and the nature and order of its mineral masses, 
and their contents accurately ascertained, described, and laid down 
in maps and sections, no one would hesitate to say, that a vast ser- 
vice had been performed, even although no theory, nor any a. 
ulation had been devised. 
The value of geological research is, therefore, very great, and that 
of geological theory is certainly much less, although it is highly in- 
teresting ; theory is constantly fluctuating with the progress of 
discovery, and until. we have discovered all the facts, we cannot be 
sure that our theories will stand. With respect to theory and no- 
menclature, there is therefore, room both for fancy and error ; but 
those who, like Mr. Eaton, have labored hard and long, in investigating 
facts, and like him, have faithfully reported them, ‘econdiog to the 
best views which they possessed at the time, are entitled to our res- 
pect and kindness, although their first sketches may possibly require 
some correction from eabsouvieis observations of themselves and 
others. The munificence of Gen. Van Rensselaer in promoting ge0- 
_ logical knowled; ze, is, so far as we are informed, without a parallel in 
any country, an d he has been fortunate in the field of geological re- 
search, in which he has employed Mr. Eaton, since it is not only 
fruitful in scientific facts, of great interest, but in substances of prime 
importance to sociéty ; and perhaps we may yet hope that coal will 
be added to the other mineral riches of this important region, al- 
though it may lie ¢ | a depth, too great to admit of its being profita- 
bly explored.* 
Yale College, June 27, 1831. 
3 = 
os See Mr. Eaton’s xcellent view of this subject, Vol. XIX. No. I. of this Joar- 
= ie & 
Pa ae a 
ed i. i& ice 
