168 Professor Keilhau on Unstratified 



ness ; but what is correct in fact cannot be rejected on that 

 account. If this epigenetic mode of formation, as it may be 

 shortly termed, were even less intelligible than it really is, if 

 even also there were no prospect of our understanding it better 

 in future than we do at present, yet we ought to find no rea- 

 son in this for casting away the result that has been obtained ; 

 for, as it is entirely a matter of fact, it must remain, however 

 burdensome it should become in regard to its farther expla- 

 nation. 



It is not my intention to discuss fully here all the facts 

 which shew that the unstratified rocks containing quartz, and 

 composed of crystallized silicides, are transmutations of what 

 were originally sedimentary, or perhaps also partly eruptive 

 masses ; but the position of the matter is such, that the most 

 important at least of these facts must here be brought to the 

 recollection of my readers. 



1. Granite, syenite, greenstone, porphyry, amygdaloid, 

 &c., are often found connected, by gradual transitions, with 

 stratified rocks, which partly in a direct, partly in an indirect 

 way, present themselves as formations, which were originally 

 deposited by water. The most striking phenomenon of this 

 kind is when the unstratified rock is entirely surrounded by 

 sedimentary strata, of which some with their terminations, and 

 others with their hanging or lying sides, gradually pass into 

 the epigenetic mass. The assertions that have been made 

 regarding these occurrences, for the purpose of supporting the 

 eruption-theory, are quite contrary to nature. Among the 

 most frequent of the transitions where the stratified rock can 

 directly be recognised as of ordinary hydrogenic origin, are 

 those from fossiliferous clay-slate into diorite and other green- 

 stone rocks. Of those from strata which can only be indirectly 

 recognised as hydrogenic, the transitions from gneiss into 

 granite are the most usual. Here, however, the phenomenon, 

 certainly in most cases, is to be understood in this way, that 

 one portion of the original hydrogenic deposit was converted 

 into gneiss, while other neighbouring portions assumed the 

 character of granite, which two rocks, by means of their 

 close mutual relationship, can of course easily run into each 

 other at their common boundaries. In Norway, there are 



