Professor Keilhau on Contact Products. 143 



Deity, the First Author of all things, the Regulator of the 

 whole world, the Dispenser of all blessings ? Such at least is 

 the truth which my feeble intelligence reads in the works of 

 creation, when I contemplate them with a grateful heart. It 

 is a sentiment, moreover, which better disposes us to search 

 for the truth, and seek it for its own sake ; and I am convinced 

 that if, in the study of the natural sciences, inquirers less fre- 

 quently dispensed with touching upon these questions, even 

 in the special domain of direct observation, their progress 

 would generally be more certain and more rapid.* 



On the Mode of Formation of Crystalline Limestone^ Contact 

 Products^ Crystalline Silicide-Slates, and unstratified Crys- 

 talline Silicide-Bocks ; with Preliminary Observations on the 

 present state of Geology^ and on the Methods of Investigation 

 pursued in that science. By B. M. Keilhau, Professor of 

 Geology in the University of Christiania. Communicated 

 by the Author. 



(Concluded from vol. xxxvi. p. 362.) 



Contact Products. 

 Besides the crystalline limestones just discussed occurring 

 at the junctions of rocks, there are, as is well known, a 

 number of other mineral substances, which present them- 

 selves close to various mountain rocks, in such a manner, as 

 to lead us to conclude that the proximity of the latter has 

 had some direct participation in the production or modifi- 

 cation of these substances. If geological knowledge were 

 founded entirely on chemistry ; if it is forgotten that the 

 latter science is still so far from having reached that perfec- 

 tion which alone would enable it to solve all the chemico- 

 geological problems ; if we are to reject the demand arising 

 out of the very nature of the case, that geological phenomena 

 must first of all be taken into consideration in the establish- 

 ing as well as in the acquiring of geological knowledge, then, 

 in our opinion, this knowledge would not only be checked 



* From Recherclies sur les Poissons Fossiles par L'Agassiz. Demiere 

 Livraison. 1843. 



