Geology and Natural History. . 221 
Hamilton shales, Ca ayuga Lake ; mulator Ha il, from the 
Chemung, near Tthaca; G. ( cane 7 Wendel Hall, ‘same slonek- 
ity; G. Chem ungensis, var. eguicostatus, from the Chemung of 
inary Report on the First Season’s Work of the Geo- 
logical ai of Yesso ; B. 8. Lyman. 46 pp. 8vo. Tokei 
874.—B 
Tle then n gives an outline of the manner in which the various 
alterations in a mine cies may take place, by replacement, 
Se and epigenesis, with examples for each, and dwells at 
more length upon the fallacy of considering the alterations of 
many minerals and rock masses as the r of an epigenic a 
cess ; a doctrine which has been embodied in the dictum of Pro- 
Sessor Dana: “ regional metamorphism is pseudomorphism on a 
broad scale.”* 
*Mr. Hunt knows that this “dictum of Prof. Dana,” as he calls it (which 
is a clause in a sentence of a -notice written by me in this Journal, xxv, 
445, 1858), does not represent at all the views on metamorphism that I have held 
r the past twelve years ; for, err having given him a copy of my Geology in 
1862, I took especial pains, in in my review. of his American Association 
Address, to refer him to the eae on Metamorphism in the work, that he 
might read and appreciate the grossness of oe p-sonesninascoasieant aot knows, 
i may be changed into grantte or its turn serpen- 
tine” (both of which he put forth in the same Address), have been shown by me 
to be . I assured him in the review and its cet tat tee 
of such transformatio: . above enumerated had never occurred to me until 
found in his que = egies st “Gustaf Rose, Haidinger, Blum, vuleee: 
