GOLD MTNIXG IN COLORADO. 507 



reason for the contrary opinion. The two branches or veins appear at the 

 surface together on the Smith and Parraelee location, and are worked between 

 the same walls for something more than 100 feet. Descending vertically from 

 that point the two diverge, the so-called Gregory dipping about 80° to the 

 northwest, the Briggs at about the same inclination to the southeast, the dis- 

 tance between them, therefore, increasing with the depth, so that at 240 feet 

 below the surface a crosscut shows them to be 72 feet apart. 



Horizontally, the two branches diverge in going eastward, the angle of 

 divergence being but a few degrees at first, and further east, so far as opened, 

 the difference in their courses being about 10° — the Gregory having a course 

 of north 45° east, true, while the Briggs has a course of north 55° east, true. 

 The line of j unction, or divergence, of the two branches on the west is not a 

 vertical one, but dips to the westward, so that with increasing depth the divi- 

 sion of the vein into two branches is found further and further west, occur- 

 ring near the surface on the western part of the Smith and Parmelee and 

 eastern part of the Briggs location, while on the Black Hawk mine the split- 

 ting of the vein into the two branches is about 300 feet further west at a 

 depth of between 200 and 300 feet below the surface. 



Eastward, beyond the Smith and Parmelee, the work has not been suffi- 

 cient, either on the surface or in depth, to determine the relations of the two 

 branches, and whether they reunite, and if so, where, remains to be seen. 



The so-called Briggs lode derives its name from the Briggs Company, 

 which is located on the Gregory vein between the Black Hawk and Smith 

 and Parmelee mines. It is said to have been discovered on this property, and, 

 as an independent lode, is understood to be claimed by that company for a 

 considerable distance beyond the limits of their claim on the Gregory itself. 

 The adjoining companies, however, holding that the so-called lode is but a 

 branch and a part of the Gregory, work it as such within the limits of their 

 claims. Some further observations concerning the relations and development 

 of these two veins or branches will be given in the following brief descrip- 

 tions of the operations of the several companies working on them both. 



The country-rock of the Gregory lode is generally similar to that of the 

 Bobtail — a granitic gneiss, sometimes poor in mica, at other times abounding 

 in that mineral, and having the appearance of mica-schist. It frequently 



