GEOLOGICAL SURVEY OF THE TERRITORIES. 177 



of which are now dry as the dusty road for the greater portion of the 

 year. I mention some of these details here simply to show how closely 

 the story of the physical growth of our western continent is linked 

 together, and that it needs only the careful, conscientious grouping 

 together of the facts to secure this history step by step from the earliest 

 commencement to the present time, and mold it into one harmonious 

 whole. 



CHAPTER XIV. 



OBSERVATIONS ON MINES— ANALYSES OF COALS, ORES, AND SALTS. 



Although many valuable observations have been made in regard to 

 the gold and silver mines of the West, I shall not attempt to present 

 them in detail at this time. The elaborate and elegantly illustrated 

 " Eeport on Mining Industry," prepared under the direction of Mr. 

 Clarence King, United States geologist of the 40th parallel, about to be 

 issued from the Public Printing Office, covers this ground far more 

 efficiently than my incidental labors could do. Mr. E. W. Raymond is 

 making a series of valuable reports as United States Commissioner of 

 Mining Statistics, and the one already published for the years 1869-'70 

 is quite exhaustive, and to these works the reader is referred. The 

 latter report contains an excellent and lengthy statement of the condi- 

 tion of the mines of the Sweetwater district. In the preceding pages 

 some information is given in regard to those mines, and in this chapter 

 a few additional notes, taken by Mr. A. L. Ford, mineralogist of the 

 survey, will be of interest. 



The object of this survey is to study the mineral regions more in 

 reference to their geological relations than with any special practical 

 end in view. 



In a previous report the remarkable parallelism of the lodes was al- 

 luded to, and an attempt was made to show that this fact is only one link 

 in a chain of facts which may yet serve to unite the physical history of the 

 mountain' regions of the West together. Hundreds of observations 

 were taken the past season, which serve to show the definite direction 

 of the two principal sets of fissures or clefts. The unity of the origin 

 of all these fissures, whether they assume the form of mineral lodes, 

 dikes, or lines of fracture of mountain ranges, is a thought around which 

 I wish to cluster all the facts that can be secured. Hereafter all these 

 observations will be carefully sifted, and Fig. 19. 



those which seem to contain the elements 

 of truth will be found valuable. 



In this connection, two illustrations of 

 these fissures may be introduced, which 

 will be of interest. They are made by the 

 Jewett line relief process, and are very 

 excellent. One of them presents a fine 

 section of the well-known Gregory lode 

 at Central City. This fissure has a strike 

 about northeast and southwest. The 

 country rock is true gneiss, while the 



gangue Of the lode is mostly feldspar and Gregory Lode, Central City, 



quartz. So far as the history of its min- Colorado. 



eral contents is concerned, it is so well known that I need not describe 

 it, and the cut will explain itself. 

 12 G 



