Ch. IX.] VEINS IN PRIMARY ROCKS. 



a vein ; and is, as in every other work, so blended with hypo- 

 thesis, that the student cannot distinguish fact from con- 

 jecture. 



This fault, both in our elementary and systematic works, is 

 certainly to be regretted : it is not, however, attributable to 

 these eminent geologists, but to the mode in which this part 

 of the science has been treated ; and their names are only 

 here adduced as authorities to show the truth of our observ- 

 ation, that the knowledge of veins is very defective. 



This stricture may not appear to apply to the descriptions 

 of those veins which occur in the primary rocks, and more 

 especially of those in Cornwall, which have attracted so much 

 attention, and have formed the theme of some essays of no 

 little merit, as those of Mr. W. Phillips and Mr. Carne. But 

 it will be found that even these local details are haunted by 

 the same evil genius, the blending of fact with hypothesis. 

 Thus, Mr. Game's paper on Veins, replete as it is with much 

 important information, is professedly framed on a theoretical 

 basis, " an attempt to ascertain the relative age of the Cornish 

 veins, on the principle that a vein which is traversed by 

 another vein, is older than that by which it is traversed." 

 So that the attention is necessarily almost entirely directed to 

 a single point, which is only one of the many interesting 

 phenomena exhibited by veins : the object of the paper has 

 been well accomplished ; but we have always thought that the 

 author would have conferred a greater benefit on the science, 

 if, from his store of practical experience, he had imparted 

 more lengthened and descriptive details of each leading 

 example. 



The student, or rather the geologist, (for who is not a 

 student on this subject ?) after having perused these papers 

 on the veins of Cornwall, returns to them again and again, 

 and still his idea of a vein is not more distinctly defined : he 

 feels satisfied, indeed, that he knows what a vein is, and so 

 does the merest tyro ; but, as in the case of the word stratum, 



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