SECTIONS OF THE NEW ALMADEN. 319 



the Quicksilver Mining Company, and data exist for the construction of 

 any desired sections. A fine opportunity is thus afforded for a study of the 

 structure of this very important deposit, and it has seemed to me worth 

 while to illustrate the occurrence very fully Ijy plans and sections. The 

 mine maps and sections which I selected as best a<lapted to show the struct- 

 ure were prepared for me from plans and notes in the office of the company 

 by Mr. Frank Reade, who was surve}'or of the mine at the time of lU}' 

 examination and who formerly assisted me in studying the Comstock Lode. 

 The ore deposits being in my opinion comparatively recent, the rela- 

 tions between their distribution and the present topography of the surface 

 are of interest. On Atlas Sheet VIII the plan of the known ore bodies is 

 shown beneath a contour map of the surface. It will be at once remarked 

 that these ore liodies ai-e divisible into four groups. Two of them, reached 

 respectively by the Washington and Cora Blanca shafts, seem to be isolated. 

 The other two groups, upon which the main mine has been opened, are very 

 closely connected. The more important group of the ore bodies of the 

 main mine reaches from the top of the Mine Hill nearly to the Santa Isabel 

 shaft and is substantially continuous for the entire distance. The croppings 

 at whicli Castillero and others before him found cinnabar, as was narrated in 

 Chapter I, were at the top of Mine Hill. A monument at this point is used 

 as the datum to which the contours and mine levels are referred. The other 

 group of ore bodies of the main mine lies to the east of the Randol shaft- 

 I shall have frequent occasion to distinguish these two sets of ore bodies 

 and shall refer to them as the north and south groups. Tins map is printed 

 on a scale of 300 feet to the inch and the contours are drawn at vertical 

 intervals of 10 feet. The plan of the workings is given on Atlas Sheet IX, 

 this and the succeeding sheets being drawn on a scale of 150 feet to the 

 inch, or double that of the topographical map on Sheet VIII. The highly 

 complex, structure of the separate ore bodies is very apparent from this plan 

 as well as the existence of tertain sui-faces along which the ore bodies are 

 grouped. The colors and figui'es make explanations needless. I have not 

 tried to indicate on this plan or on the sections the character of the wall rocks, 

 for nothing could result from such an effort. The entire mass of the country 

 rocks consists of metamorphosed sediments. Every stage of metamorphism 



