318 QnCKSILVER DEPOSITS OF THE PACITIC SLOPE. 



reach, and he will find nothing to conflict with them in any portion of the 

 mine. 



Certain features must be common to the ore bodies taken singly and to 

 the ore-bearing ground as a whole. It would be impossible to supjjose that 

 each stockwork has an independent fissure system, and a mere glance at the 

 mine maps shows that a connection between them exists. It is also a his- 

 torical fact that the thin seams of ore (stringers or, as the Spanish miners 

 call them, hilos) have led fi-om one ore chamber to another. There must be 

 a general fissure svstem, in subordination to which the various ore bodies 

 are arranged, and this system must stand in the closest relations to the gen - 

 eral geology of the countrv. Such a system can result only fi'om a some- 

 what widespread disturbance and, it is superfluous to remark, must have been 

 formed according to ordinary mechanical laws. I£ the rock of the country 

 were thoroughly homogeneous and were level at the surface, a fissure caused 

 by a simple distm-bance would follow a straight line and would pass over 

 at its extremities into a fold. Under a sufficient horizontal stress such a 

 country would show a system of parallel fissures passing into a common 

 fold at each end. Fissures thus tend to straight lines and parallel systems, 

 but this tendency is modified by inequalities in the properties of the rock 

 and in the configuration of the surface. It is often difficult to decipher 

 the fundamental fissure system in a country of heterogeneous character, 

 but this does not seem to be the case at New Almaden. 



The distribution of serpentine, the average strike of the metamorphic 

 strata, the compression of the iliocene beds, the position of the rhyolite 

 dike, and the trend of the range, in short the whole structural geology of 

 the region shows that the fundamental axis of disturbance must have a 

 direction which is approximately northwest and southeast. It is along a 

 fissure, or a svstem of parallel fissures, taking this general direction, but 

 more or less deflected by local causes, that ore might be expected to occur 

 in such a district It is on such a line that the Xew Almaden, Enriquita, 

 and Guadalupe deposits occur. In the Xew Almaden mine itself, also, there 

 appear to me clear evidences of a fundamental fissure system. 



piaas aad saitioas of the New Almaden. — Thc surface and the workiugs of the Xew 

 Almaden mine have been surveved with the utmost care bv the officers of 



