MUSEUM OF COMPARATIVE ZOOLOGY. 131 



The theories of the igneous origin of the veins, and of the igneous 

 deposition of the copper in them, have been so ahly refuted in the vari- 

 ous papers referred to liere that it is unnecessary to discuss thcni ; but 

 owing to the great weight of Professor Dana's name, we cannot pass 

 over liis theory without saying that the supposed facts on which it is 

 based do not exist in tlie Copper district, he having raised the super- 

 structure on the errors of Messrs. Houghton and Jackson, never having 

 visited the region himself. 



As in the Iron district, so in the Copper district, the writings of 

 Messrs. Foster and Whitney remain the best and most accurate expo- 

 nents, as they were the first of vahie, of the geology of the country, and 

 of the ore deposits studied by us, so far as they were known at that time. 

 All work since, so far as it stands the test of examination, sustains their 

 views and establishes the accuracy of their observations, except in a few 

 particulars. Mr. A. R. Marvine's work stands next in oi'der of value 

 and geological ability shown. 



Professor Pumpelly deserves all credit for his microscopic examina- 

 tions of the old basaltic rocks of the district, and for the extent and 

 thoi'oughness with wliich he has applied and carried out the investiga- 

 tions and theories of Messrs. Whitney, MUller, and Bauerman, in his 

 " Paragenesis and Derivation of Copper and its Associates on Keweenaw 

 Point " ; but his stratigraphical work was not worthy of the name, and 

 served only to obscui-e the true relations of the rocks. The volcanic 

 origin of the rocks was proved by Marvine five years before, by Foster 

 and Whitney twenty-eight years before, and announced by Hubbard 

 thirty-two years before Pumpelh' accepted it. 



Our work pi-oves that the Keweenawan system has no foundation 

 except in insufficient observation and the application of stratigraphi- 

 cal methods and assumptions that will not bear exaniinatiun. Tlie 

 difficulty here, as in the Iron district, has been in tlie methods, and 

 in the assumption that certain observations proved that which they 

 did not. 



I desire to extend my thanks for fiivors received while in the Iron and 

 Copper districts to Charles E. Wright, M. E., State Commissioner of Min- 

 eral Statistics; Per Larsen, M. E. of the Jackson mine; Agents C. H. Hall, 

 of the Lake Superior mine, William Sedgwick, of the Barnum, D. H. 

 Bacon, of the McComber ; Capts. James Pascoe, of the Champion, and 

 Peter Pascoe, of the Republic ; also to Mr. David Morgan, President of 

 the Republic Iron Company ; to Captain Clifi", and L. G. Emerson, M. E. 



