290 QUICKSILVER DEPOSITS OF THE PACIFIC SLOPE. 



around the basalt area in a manner which indicates a reLation between ore 

 deposition and the eruption. At Mt. Amiata, in Tuscan}'-, also, cinnabar 

 deposits occur along the edges of a field of lava and are younger than the 

 eruption. There is information, believed to be trustworthy, that cinnabar 

 in the Lake mine was deposited at the contact between a basalt dike and 

 the inclosing rock, and therefore later than the basalt. Mineral springs 

 still issue close to the basalt and deposit sinter, the composition of which is 

 similar to that of the matter held in solution by the hot springs at Sulphur 

 Bank. The Redington, Reed, and Andalusia mines, with the fissure from 

 which the basalt issued, form a nearly straight line. There can scarcely be 

 a doubt of the escape of hot solfataric gases into the workings of the Reding- 

 ton, and the structure of the Redington ground is such as seems readily ex- 

 plicable if the ore has been deposited at a time so recent that little erosion 

 has since taken place, but very difficult of comprehension on any other sup- 

 position. These facts seem to me to warrant the conclusion that the cinna- 

 bar deposits were consequences of the basalt eruption and that the course of 

 deposition was entirely similar to that of Sulphur Bank. 



This conclusion is particularly important because of the existence of 

 most unmistakable veins at the Redington mine. The upper part of the 

 deposit corresponds to and greatly resembles the underground developments 

 of Sulphur Bank. The lower workings at Knoxville develop typical veins, 

 which are continuous with the stockworks near the surface. The two foi-ms 

 of deposit, which are also associated at the great Austrian mine, were here 

 formed at the same time and by the action of hot sulphur springs. True 

 veins of ore may then be deposited from hot spring waters. It also follows 

 that true veins jjrobably underlie the Sulphur Bank. 



Future prospects. — At tlic tiiuc of uiy examiuatiou the Redington siiowed 

 little ore. This seemed to me very largely due to insufficient prospecting. 

 I do not think a great ore body such as that at the surface will ever again 

 be met in this mine, but I have no reason to suppose that it is exhausted 

 or that important masses of ore are not still to be found at or near the prin- 

 cipal fissures. 



