48 T. 8. Hunt on the Criticisms of Prof. Dana. 
With these citations before us, and remembering the views 
Scheerer, and the later ones of Delesse, together with the lan- 
guage of the latter in his essay on Pseudomorphs, let us no- 
tice the words of Naumann, addressed to Delesse in 1861, in 
allusion to the essay in question. “Permit me to express to 
ou my satisfaction for the ideas enunciated in your memoir on 
seudomorphs, ideas which my friend Scheerer will doubtless 
share with myself” (idées gue mon ami M. Scheerer partagera 
sans doute comme mot-méeme). en follows the language which 
I have quoted in my address, in which he combats the error of 
those who hold that gniesses, amphibolites, and other crystalline 
rocks are “the results of metamorphic epigenesis, and not ori- 
ginal rocks,” and adds, “It is precisely because pseudomorphism 
has so often been confounded with metamorphism that this error has 
found acceptance.” [Bull. Soe. Geol. de Fr., II, xviii, 678]. 
The reader must now judge whose opinions it is that are here 
denounced as erroneous, and whether Naumann was on the side 
and 1860, already referred to. But while it has been generally 
admitted that what, in my address, I have called the first class 
of crystalline rocks (consisting chiefly of quartz and aluminous 
silicates) might result from the molecular re-arrangement of the 
elements of clay and sand-rocks, I maintained in those papers that 
what I have called the crystalline rocks of the second class 
(in which protoxide silicates predominate) have been generated, 
by asimilar process, from deposits of chemically-formed silicates. 
This view being adopted by Delesse and by Giimbel to explain 
