ORIGIN OF ERUPTIVE AND PRIMARY ROCKS. 465 



" The primitive formation appears to possess quite an extraor- 

 dinary thickness ; and to reach very far down into the depths of the 

 earth. At the same time it shows in a remarkable manner, in those 

 different regions where it comes to the surface, such a general resem- 

 blance as regards its rocks, their structure and form of stratifica- 

 tion, that one is led from this alone to think that some stupendous 

 process must have taken place over the whole surface of the earth, 

 at the same time and in the same manner, and that it is to this 

 process that the primitive formation owes its existence ; and even, 

 although it may be so completely covered over in regions of im- 

 measurable extent that in these it is not observed to come to the 

 surface, still we are entitled with complete justice to suppose the 

 existence of an uninterrupted extension of the same, under all the 

 sedimentary and eruptive formations with which we are acquainted- 

 "The necessity of a primitive formation is besides so appa- 

 rent that one can scarcely comprehend how its existence could 

 ever be doubted. It appears, in fact, to be a first and indispensa- 

 ble condition, without which the possibility of sedimentary, as well 

 as of eruptive formations cannot be comprehended. The primitive 

 formation has also been, by different authors, entitled the prozoic, 

 azoic or hypozoic formation, because it existed long before the com- 

 mencement of the first races of animals or plants, and therefore 

 contains not a trace of organic remains, and lies beneath all fossili- 

 ferous formations. But all eruptive formations are likewise azoic; 

 the oldest sedimentary formation is likewise prozoic, and the term 

 hypozoic is perhaps a word which does not correspond sufficiently 

 well with the idea intended to be expressed by it." 



"It is possible for us to regard the primitive formation perhaps, 

 as the uppermost part of the original solidified crust of our planet ; 

 and this supposition has here and there been adopted. We leave, 

 however, the process of their formation undecided, and rest satis- 

 fied, in the meantime, with the negative result, that according to 

 the present condition of our knowledge, the primitive formation 

 can neither be a sedimentary formation, in the usual signification 

 of the term, nor yet an eruptive formation, properly speaking. It 

 is however a most remarkable fact, that a few comparatively 

 far younger formations show a surprising similarity to the primi- 

 tive formation in the structure and architecture of their rocks, 

 (viz., the Miinchberg gneiss-formation in Oberfranken, and the pro- 

 togine formation of the Alps). This fact, as well as the circum- 

 stance, that they are almost all cryptogenous or stratified crystal- 

 Can. Nat. 31 Vol. VIII. 



