Merrill.] 
234 
[October 19, 
CONCERNING THE LITHOLOGICAL COLLECTION OF THE 
EXPLORATION OF THE FORTIETH PARALLEL. 
BY N. F. MERRILL. 
In the quotations, throughout, all insertions within brackets as well as all emphasis 
expressed by italics have been introduced by the writer of this paper. 
Almost simultaneously with a partial study of this collection 
which it was my privilege to enjoy, a paper came to my notice 
entitled : “ On the Classification of Rocks, by M. E. Wadsworth,’ 
published in the Bull. Mus. Comp. Zool., Harv. College, Cam- 
bridge, Mass., Vol. V, No. 13. Since that paper dealt largely with 
this same collection and contained statements concerning it with 
which my own studies cause me to disagree ; and since, aside 
from this, the paper expresses views which seem to be somewhat 
peculiar, I have been led to offer the following remarks. 
A note appended to the title of Mr. Wadsworth’s paper, on 
page 275 of the Bulletin, reads : “Abstract of a thesis presented 
for the degree of Doctor of Philosophy in Harvard University, 
March 25th, 1879 ; also given before the Boston Society of Nat- 
ural History, May 7th, 1879. The references and the numbers of 
the sections, which are fully given in the original, are omitted 
here.” 
On page 278 the author remarks: “Since, owing to the ne- 
cessities of the case, both in the use of these observations in a 
thesis and in giving a post-graduate course in lithology in this 
museum, my work was made public before it was entirely com- 
pleted, it has been deemed necessary to publish this abstract in 
advance. Several matters of detail yet remain to be worked 
out, which may modify some of the general views. All that is 
liable to be so modified must, therefore, be withheld for the pres- 
ent.” From the last sentence it may be concluded that whatever 
is not withheld, is not liable to such modification. One is justi- 
fied, therefore, in proceeding to weigh the statements of the pres- 
ent abstract, entirely divested of any fear of undue precipitation. 
On page 279 of the Bulletin, we find the words : “ . . . form- 
ing a base called by the German lithologists 4 microfelsitic.’ 
Under this term they have utterly confounded the original micro- 
