222 GEOLOGY. 



Geological Survey, and the withdrawal of appropriations from all pre- 

 viously existing surveys. There was much discussion and some feeling 

 excited in the selection of a suitable director for this survey, though the 

 appointment of Clarence King, w^ho is so well and favorably known for 

 his excellent geological work upon the fortieth parallel, produced gen- 

 eral satisfaction. He immediately organized a working force for geo- 

 logical investigation in the public domain, and although the new survey 

 has as yet made no reports, the well-known ability- of the gentlemen who 

 are at work in this field is an assurance of many and valuable contribu- 

 tions to science. In the mean time the old surveys have been permitted 

 to finish their work, and the result is the addition of several volumes to 

 the geological literature treating of the Western Territories. 



Several of the State surveys have issued volumes. The work of the 

 large and active corps engaged upon the Pennsylvania survey has 

 been already noticed. If in speaking of this and other work by surveys 

 I am unable to give any details of their interesting discoveries on ac- 

 count of their number, it is none the less important to draw attention 

 to the volumes from which information can be obtained upon the struct- 

 ure and resources of some of our most important territory from an 

 economic standpoint. 



The Wisconsin survey has published a large and valuable volume, 

 which contains work by Irving, Pumpelly, Brooks, Wright, and others, 

 and which gives much information concerning Lake Superior formations 

 and their constituent rocks. The nature and origin of the Lake Supe- 

 rior iron ores and copper ores have always been subjects of much inter- 

 est. Foster and Whitney early examined and reported upon these de- 

 posits, but for many years tlie testimony of students has been such as 

 to convince that, in opposition to the views of Foster and Whitney, the 

 iron ores are metamori^hic strata, and that the copper was introduced 

 into the diabases and sandstones by solutions of copper salts and there 

 reduced to metal and deposited. Mr. M. E. Wadsworth, however, has 

 reopened the question, by having reached the conviction that the iron 

 ores are eruptive rocks, as advocated by Foster and Whitney, and that 

 the copper also was an accompaniment of the eruption of the diabases. 

 Although few are found at present to agree with Foster and Whitney, it 

 is thus seen how difficult it is to establish beyond dispute even the sim- 

 X^lest questions of geological structure. The volume on Wisconsin 

 geology treats the iron ores as met amorphic schists, and contains a 

 great deal of careful lithological and stratigraphical work. 



It will be remembered that the geological survey of California, which 

 was long directed by Prof. J. D. Whitney, has been discontinued. 

 What the State refused to do has, hovrever, been pushed forward by 

 the private enterprise and energy of Professor Whitney, aided by Har- 

 vard College. His volumes upon the auriferous gravels of the Sierra 

 Nevadas is a very valuable contribution to science, since it treats of the 

 gravels from a geological standpoint, and also of the modes of working 



