BY LEO A. COTTON. 761 



•observed were 1 inch in thickness. About 75 per cent, of the 

 veins are between 6 aud 18 inches in width. A number of 

 -expanded masses of reef- material, of a circular or ovai shape, are 

 of frequent occurrence. These are to be found chiefly at the 

 intersection of two reefs, but also occur as bulges on the line of 

 reef, or as isolated patches. These " blows," as they are called, 

 are represented in text-fig. 2 as black patches. This type of 

 reef is not limited to, or excluded from, any of the fracture- 

 systems represented at Elsmore, though the largest veins conform 

 mostly to the system N.43°E. It cannot be said that any of the 

 reefs show great uniformity, — rather the contrary. Most veins 

 are from 2-3 chains in length. As no shafts have been sunk on 

 this area, the reefs are not exposed vertically, save in a few 

 shallow trenches. In these the reefs appear to be vertical. In 

 only three cases were dips noticed, and of these one dipped 

 E.43°S. at 63°, another E.4r.S. at 61°, and the third E.25'S. at 

 53^ 



The country-rock is a coarsely crystalline granite, which is so 

 decomposed at Elsmore that it is impossible to obtain a hand- 

 specimen anywhere from the area shown in text-tig. 2. A few 

 .hundred yards to the east of this area, fresh granite may be 

 obtained, and is typically the coarse "Acid Granite" previously 

 described. 



None of the reefs have been systematically worked, only the 

 surface-shoots having been mined. There is probably no single 

 reef which would pay for working, but, on the eastern slope of 

 iElsmore Hill, the reefs are so close together that the whole might 

 be worked by an open cut. The exact tin-content of the reefs 

 could only be determined by a very large bulk-sample. 



The reefs appear very similar to those occurring both in the 

 Stanthorpe district to the north, and at Mount Rex in Tasmania 

 to the south. Indeed, descriptions of the occurrences in these 

 districts, coupled with the examination of hand-specimens, render 

 it abundantly clear that the same processes have been active in 

 the vein-formations of all three areas. Though well defined as 

 reefs to the casual eye (see Plate Ixi., Hg.l), a close examination 



