1874.] 169 [Dana. 



1872, that it did not express the opinions on metamorphism which I 

 had held for the past twelve years; and I referred him to the chapter 

 on metamorphism in my Manual of Geology, a copy of which I gave 

 him in 1862, that he might read, and so become aware of the gross- 

 ness of the misrepresentation. And yet he repeats it in 1874, with- 

 out a qualifying remark. 



So again, as to the statement that " the advocates of this doctrine 

 maintain that a mass of granite or diorite may be converted into 

 serpentine or limestone, and that a limestone may be changed into 

 granite or gneiss, which may in its turn become serpentine : " I as- 

 sured him, in letters addressed to him in the autumn of 1871, in my 

 notice of his Address (Am. Jour. Sci., in, 86, 1872), and in the Se- 

 quel to it (Am. Jour. Sci.. iv, 97) that I had never held such views ; 

 and, further, that the idea of such " transmutations " had never oc- 

 curred to me until found in that Address, in his charge against 

 u Gustaf Rose, Haidinger, Blum, Volger, Eammelsberg, Dana, Bis- 

 chof, and many others." And yet he repeats it without qualifying 

 remark. 



I have also demonstrated, from the writings of Gustaf Eose and 

 others, that they have never expressed the extravagant view attrib- 

 uted to them ; and the same could be shown for all writers on the 

 subject, excepting Bischof and one or two others. Bischof s state- 

 ment about the change of limestone to granite I had overlooked until 

 Mr. Hunt's remark called my attention to the subject. 



Mr. Hunt, in an article in Volume iv of the " Journal of Science" 

 (1872), endeavored to substantiate the charge that / had virtually 

 sustained the metamorphism of granite or gneiss to limestone, by saying 

 that I state in my mineralogy, 



First, that calcite is sometimes found pseudomorphous after quartz ; 

 and, 



Secondly, that calcite is found pseudomorphous after feldspar. 



Then he made these two alleged statements about isolated pseudo- 

 morphs of calcite after quartz and feldspar (leaving the mica of 

 granite wholly out of consideration) proof that I virtually believed 

 in the change of granite or gneiss to limestone ! The truth is, that 

 I have no such statement in my Mineralogy as that calcite is ever 

 found pseudomorphous after quartz ; and the pseudomorph of calcite 

 after feldspar is spoken of as an example, not of the alteration of 

 the feldspar, but of its replacement or removal. Such is the whole 

 demonstration ; such its scientific character. 



