Zirkel.] 110 [November 1, 



worth's method of criticism was highly objectionable and that 

 some of his statements appeared to indicate that he lacked the 

 proper qualifications for his work. 



Now, however, that Mr. Wadsworth in a second paper x " Some 

 points relating to the Geological Exploration of the Fortieth Par- 

 allel " continues his peculiar criticism in a still more striking man- 

 ner, I think it proper to put into form, as my first and last words 

 in this matter, the following points. 



1. The chief reason for the difference between Mr. Wads- 

 worth's determinations and my own consists in that — to use his 

 own words — "the writer (Wadsworth) rejects the common lith- 

 ological method " (b. 245) ; that is, he does not admit, that, in de- 

 termining a massive rock, not only its mineralogical composition 

 and its structure, but also its geological age, should be regarded, 

 or that there exists a difference between the habitus of the pre- 

 tertiary rocks, and that of tertiary and post-tertiary rocks, a 

 contrast which has found its ample expression in our old and 

 generally adopted terminology. Surely I cannot be called to 

 account for adhering to this common lithological method which 

 I consider far more reasonable and natural than Mr. Wadsworth's 

 " new classification." With a geologist like Dr. Wadsworth, who 

 does not believe in any ante-tertiary precursor of andesite, basalt 

 trachyte or rhyolite (b. 258), who wishes that the name diorite 

 may soon be dropped (a. 279), who uses the terms melaphyre 

 and diabase to indicate altered and therefore generally old ba- 

 salts (b. 259), and who even considers the peridotites as altered, 

 coarsely crystaline basalts (a. 279) — with such a geologist all 

 possibilities of further scientific explanation and discussion is pre- 

 cluded. The standpoints of the customary and of the " new " 

 classification are so far apart, that I decline to enter into special 

 debate. 



2. Mr. Wadsworth demands that my work, written in 1875, 

 should conform to his extraordinary principles published by him 

 in 1878 in an abstract in which he utterly rejects the method of 

 petrography as taught to-day. 



3. Mr. Wadsworth is entirely wrong in saying : " It is to be 

 remembered that Richthofen's and King's classification is not ac- 



1 Ibid p. 243, (b). Mr. Wadsworth's papers will be referred to by the use of the 

 letters, a and b. 



