Merrill.] 
454 
[April 6, 
made, without even specifying a single number 1 of the specimens 
examined, and the method of allowing such charges to circulate 
freely in that condition for two years ! 
Mr. Wadsworth has explained that I misunderstood his mean- 
ing in the phrase : “ original microfelsitic base of the unaltered 
andesites,” 2 and states in his second paper, page 244 : “ the word 
original was used in direct opposition to the terms alteration 
and devitrification in the same sentence, and had no reference to 
the 4 original use ’ of the term microfelsitic. The word original 
meant in the sentence, that which was believed to be* the direct 
product of the cooling magma, in contradistinction to that which 
was the product of subsequent changes in the rock.” 
Two pages further on, however, in the same paper which con- 
tained the phrase “ original microfelsitic base of the unaltered 
andesites,” he alludes to the “ so-called microfelsitic base ” as being 
a devitrification product of the glassy base in the older and more 
altered rhyolites. Hence, since Mr. Wadsworth refers in one and 
the same paper to a devitrification product in the rhyolites as the 
“so-called” microfelsite, and to an “original” (i. e. unaltered , 
non-devitrified) microfelsitic base of unaltered andesites, it is 
evident that he regards the devitrification product in the rhyolites 
only as the “ so-called ” microfelsite and considers the real micro- 
felsite to be the non-devitrified base of the “ unaltered andesites.” 
Mr. Wadsworth has given in his second paper some of the 
numbers of the specimens examined by him and, occasionally, 
his own microscopic determinations. The specimens thus men- 
tioned by him I have again studied, and some of the more 
interesting ones may now be noticed. In what follows it should 
be said that, wherever any suggestion touching classification is 
made by me, such suggestion is intended to be made in accord- 
ance with customary principles of classification and not in 
accordance with Mr. Wadsworth’s new classification, since no 
new classification of which the principles have been only “ briefly 
sketched” can have that strong hold upon us that we should 
forsake the customary principles. 
1 Excepting three numbers concerning which Mr. Wadsworth agreed with the deter- 
minations. Bull. Mus. Comp. Zool. Harv. Coll., Vol. v, No. 13, p. 286. My statement 
(These Proceedings, Vol. xxi, p. 238) that Mr. Wadsworth had specified no numbers 
of specimens examined by him Avas, therefore, inaccurate. 
2 Bull. Mus. Comp. Zool., Vol. v, No. 13, p. 279. 
