776 THE TIN-DEPOSITS OF NEW ENGLAND, N.S W., I., 



the shaft, and consists of a friable felspathic rock containing a 

 good deal of quartz. This latter mineral is' of the clear glassy 

 type, and is crystallised in small prisms up to nearly an inch in 

 length. The country-rock is the same as at Hong-Hay's Pipe. 



These pipes are of a rather different nature from those described 

 from the Transvaal, by Kynaston and Mellor.* These gentlemen 

 have described a number of very interesting pipes, characterised 

 by intense alteration of the granite in which they occur. In 

 many of these pipes a characteristic zone of tourmaline borders 

 the outer edge of the pipe, w^hile the central portion consists 

 chiefly of quartz and mica. It is possible that some of the 

 Transvaal pipes, in which this tourmaline-ring is absent and the 

 central filling is chiefly quartz and felspar, may be similar to 

 those occurring at Tingha. These are regarded in the Transvaal 

 as the simplest and least altered type of pipe-formation. 



Class X. — Cassiterite- Veins in Slate. 



Another type of deposit occurs in the slates, near the junction 

 with the granite, about 3 miles south of Elsmore. Here the 

 slate is intersected by minute veins, about 1 mm. in thickness, 

 which consist of solid cassiterite. The mineral is sharply marked 

 off from the slate, which does not appear to have suffered any 

 change near the vein. These bands of cassiterite are too few and 

 far apart to pay for economic working. 



Class xi. — Stannite-Deposits. 



Only one deposit of t^his nature is known; this occurs at the 

 Conrad Stannite Mine, near Howell. The lode is a true fissure- 

 deposit in granite, and is primarily a lead-silver ore-body. The 

 stannite occurs as a minor constituent of the lode, and is 

 associated with galena, zinc-blende, arseno-pyrite, and copper- 

 pyrites. 



* Kynaston, H., and Mellor, E. T., "The Geology of the Waterburg 

 Tin-Fields." Memoir No. 4. Geological Survey of Transvaal, Department 

 of Mines. 



