GOLD MINING m COLOEADO. 509 



The distribution of the ore is variable, sometimes occurring in seams 2 

 or 3 inches wide with intervening bands of poor rock, sometimes expanding 

 to 2 feet or more in width, sometimes pinching out altogether, leaving the 

 vein filled with barren matter, consisting of hard quartz and feldspar. The 

 pay-seam is usually on one wall or the other, but does not seem to follow 

 either uniformly throughout the length of the lode. The prominent working 

 mines on this lode are, beginning about 600 or 700 feet northeast of the junc- 

 tion with the Mammoth lode, as follows: 



Feet. 



Narragansett 400 



Consolidated Grregory 500 



Black Hawk 300 



Briggs 250 



Smith and Parmelee 300 



Southwest of the first named of these are other claims, covering in all 

 more than 1,000 feet, on which some work has been done, while northeast of 

 the last named the lode has been claimed and somewhat developed for another 

 thousand feet, but all of these claims were idle at the time of the writer's 

 visit. 



A longitudinal section of the lode will be found on Plate XXX. This 

 section is not prepared from actual survey. So far as the writer is informed 

 no careful survey has ever been made of any of the mines on the lode, and 

 the existing records concerning the occurrence of ore in the vein are very 

 meager. The section here given is prepared from verbal statements made to 

 the writer by officers of the mines. Some of the notes were obtained in 

 1868, and the sketch here given does not claim to represent with unquestion- 

 able accuracy the extent of ground that has been worked out. It is the 

 object of this section, as well as of the other two on the same Plate, to repre- 

 sent in a more impressive manner than can be done by verbal statement, the 

 length, relation to each other, and the general manner of development of the 

 several claims on three of the most important lodes of the district. Espe- 

 cially the Bobtail and portions of the Burroughs are striking illustrations of 

 the disadvantages of subdividing such veins as these into short, independent 



