ACADEMY OF NATURAL SCIENCES. 381 



sesquioxdes of chromium and aluminum with carbonic, silicic, and sulphuric 

 acids. The oxide of manganese and sulphuric acid exist only as traces. The 

 mineral is probably new, and must be referred to the mica section of an hydrous 

 silicate. Should it, on a careful chemical examination, prove to be new, I 

 would suggest the name Mariposite as an appropriate name for it, as it was on 

 the Mariposa estate that it first attracted my attention, and where it exists 

 in great abundance. 



This species which is so characteristic of the mother vein, in connection with 

 magnesian or chloritic rocks, occurs nowhere so far as I have observed in this 

 vein when it is inclosed in argillites or syenites. 



Of sulphides occurring in the mother lode there are two classes which deserve 

 special mention, beside the ordinarily occurring pyrites of iron and copper. 



These are the (1) antimonial copper sulphides, and the (2) autimonial lead 

 sulphides ; both are arsenical and are rich in both gold and silver. 



To the first class allusion has already been made in the former part of this 

 paper. Besides the Rawhide Mine, they are found in most of the openings ou 

 Whisky Hill, in Tuolumne County, in the Silver, App and Josephine, and Pine 

 Tree Mines. The lively staius of blue malachite, seen at Williams' Mine, on 

 Whisky Hill, and occasionally elsewhere, are derived from atmospheric decom- 

 position of the antimonial copper sulphides. The blowpipe detects the presence 

 of iron, antimony, arsenic, copper, sulphur, tellurium (in certain cases) sulphur, 

 gold and silver. The vein is so abundant as to give to the raw ore, in some 

 cases, magnetic properties ; and the button from the blowpipe assay becomes 

 strongly magnetic. 



The antimonial lead sulphides occur in considerable abundance at the Trio 

 Claims, on Whisky Hill. The appearance of this ore recalls that of granular 

 galena. The gold and silver value of this ore is very high, but no portion of it 

 can be saved by the ordinary mechanical treatment with mercury. The blow- 

 pipe detects the presence of antimony, lead, iron, arsenic, sulphur, gold and 

 silver. There is no trace of copper, and the quantity of arsenic present is 

 slight. The ore is therefore essentially an antimonial lead sulphide, rich in gold 

 and silver. 



There is good reason to believe, that as this remarkable vein becomes more 

 thoroughly explored, it will disclose other new or rare compounds containing 

 gold, and that these already noticed will be found to be more widely diffused 

 when proper care is applied to the study of the mineralogy of the lode. 



In Amador County the mother lode is found in connection with argillaceous 

 slates and syenite. Thus at the Eureka Mine, of Hayward, kuown as the 

 Amador Mining Co., the vein has a soft, black slate for its foot wall and a 

 heavy, firm syenite or greenstone (called granite by the miners) for the hanging- 

 wall. The mineralogy of the vein is extremely simple, being in fact nothing- 

 more than iron and copper sulphurets, chiefly the former, with rarely galena or 

 blende. I sought in vain for any of the species mentioned in the former part of 

 this paper. There are no magnesian minerals, and the Mariposite is entirely 

 absent. The other mines of that range, as far as I examined them, all partake 

 of the same simplicity in mineralogical character. There can be but little 



