REVIEWS 131 



sedimentary jaspilyte from the chemical precipitation of silica, this 

 grading into other sedimentary rocks; the derivation of the granites 

 of the Archean from metamorphism and fusion of Archean sediments ; 

 the supposed origin of the alkaline quality of these first sediments 

 being in the atmosphere, as the basal crust could not have afforded 

 them; the derivation, in the same manner, of the gabbro and asso- 

 ciated basic igneous rocks, from the metamorphism and fusion of the 

 greenstones with their clastic variations ; the addition of a large num- 

 ber of minerals to the known mineralogy of Minnesota. 



Of economic and educational results the following were men- 

 tioned : the discovery of the cause of foul water in common wells 

 in the prairie region of Minnesota, and the suggestion of effective 

 remedies; the discovery, through a series of physical tests, of the 

 excellence of the Hinckley sandstone, now widely used under the name 

 "Kettle River stone." The existence and position of the Mesabi range, 

 as distinct from the Vermilion range, was pointed out in 1884. This 

 was followed by explorations which resulted in the first discovery of 

 important bodies of ore on that range. 



"But notwithstanding the scientific discoveries of the Minnesota 

 survey, and over and above all its aid rendered to economic interests, 

 it is probable that the most valuable service it has rendered to geology 

 consists in this : The illustration it has given of the establishment of 

 a state geological survey by the state legislature and the intrusting of 

 the same to the state's university. It is not an uncommon thing now, 

 but when the Minnesota survey was submitted to the board of regents 

 of the state university, it was a novel and unheard-of proceeding, and 

 its progress was scrutinized closely by the authorities of other states. 

 The original law was carried out without a single change. The plan 

 of progress and of the report which was adopted the first year of the 

 survey was faithfully carried out to completion and without a single 

 interruption, lasting a period of twenty-eight years, /. <?., from 1873 

 to 1900." 



