156 Professor Keilhau on Contact Products. 



and the oldest of the sandstones ;" and he endeavours to shew, 

 that though there are numerous other places where this ore 

 has no other connection than with the primitive rocks, yet at 

 one time the latter must certainly there also have been covered 

 by sandstone. It will be believed that this description is quite 

 fair and free from blame, when it is known that the author, not- 

 withstanding what he has adduced, regards the masses of ore 

 as veins in the primitive rocks. 



1 will not conceal, in regard to the last example o, that 

 Murchison considers the quartz-rock with which the ore is 

 associated, to have been probably influenced by a trap-rock 

 concealed beneath. He who arranges the phenomena of Na- 

 ture according to a favourite notion, instead of allowing him- 

 self to be instructed by what Nature actually exhibits, has 

 here in this manner a path prepared for him. 



Let us now proceed to the actual application of these facts. 

 They were introduced, in order still farther to prove, that there 

 is good ground for complaining of the method at present pur- 

 sued in geological investigations. Although such facts unde- 

 niably shew that the general assertion as to the volcanic* 

 origin of contact-formations is unauthorized, yet, hitherto, they 

 have not at all been taken into consideration in the question 

 regarding the production of mineral masses of this description; 

 and, nevertheless, it is, above all, cases like these which are 

 to decide the problem. It is clear that it is not where such 

 masses are, for example, met with in contact with basalt, that 

 we can hope to find a certain explanation, as to whether they 

 are pyrogenic or not, so long as basalt is considered only as a 

 volcanic rock. If such products are attended to only where 

 they occur near rocks of which it is asserted that they have 

 been in a melted condition, it is plain that geologists here fol- 

 low a course which was least to have been expected from in- 

 vestigators who profess to adopt strict philosophical principles, 

 and who maintain that they pursue a method which infallibly 

 leads to the truth. Doubtless, this course is extremely well 

 adapted for keeping up the system which has been established, 



* In making use on the present and many similar occasions of this expression 

 to which many may object, I do not think that I am essentially in error, but, ou 

 the contrary, that I am really in the right. 



