I 



Keilhau's Theory of Granite, S^c. 373 



ous shale over when it came out, and which, by the burning 

 of the carbon, was changed from black to red and light gray. 

 But this representation embraces only a small part of the 

 causes operating during these events, it gives no information 

 as to the origin of the transition-rocks, and still less of the 

 deposits above these, which bear evidence of changes, whose 

 history is lost, and cannot be restored by any theoretical 

 speculation ; for the occurrence of circumstances of which we 

 have not been witnesses, or which have not been represented 

 to us by eye-witnesses, must be lost to us. The last men- 

 tioned remain, in the mean time, altogether beyond our pre- 

 sent subject, for we have only to do with the relations which 

 present themselves in the contact of the oldest rocks with 

 those which were formed at immediately succeeding epochs. 



Scarcely any country possesses so many remarkable, and, 

 at the same time, accessible phenomena of these contact-sur- 

 faces as Norway, and certainly no geologist has so carefully 

 examined them as Keilhau. After he found that they are, in 

 the most direct manner, opposed to the Neptunian views, or 

 the Wernerian theory of the formation of rocks, he endeavour- 

 ed to explain them according to the preceding shortly described 

 Plutonian system, but he found this system so beset Avith 

 stumljling-blocks, that he found himself obliged to view even 

 this theory with doubt, and to seek to explain the phenomena 

 in another manner. After having considered various of the 

 chief phenomena v/hich seem to be irreconcilable with the 

 Plutonian system, particularly as to the Plutonian infiltra- 

 tions of the rocks referred to, which are found in strata alter- 

 nating with such as are evidently not Plutonian, where the 

 strata sometimes become quite thin, and exhibit many al- 

 ternations over each other ; also the fact of the conversion of 

 the transition-limestone containing ])etrifactioris into marble, 

 being continued to a greater distance from the pyrogenetic 

 locks, than the assumed hot condition could perliaps have 

 extended the influence of its high temperature, with manv 

 other circumstances, which our space here will not admit of 

 our .stating, he comes to the theoretical view by which he con- 

 siders these plieiiomcna can be Ijetter accounted for. The 

 description thereof is preceded by these true, and perhaps un- 

 changeably correct remarks, " tiiat tlie moment is not yet 



