126 Proceedings of tJie Royal Society of Victoria. 



At a lower level than the majestic greenstone columns at the 

 summit of Mount King William I. are the almost horizontal 

 beds of the Oarboniferous sandstones. The characteristic fossil ^ 

 are very abundant (spirifers, fenestellidfe, &c.). Immediately 

 below the columns, a section clearly shows that this sandstone 

 has been subjected to a severe baking. The rock has been 

 hardened and browned, and much resembles in consistency a 

 well-made brick. In the short time at our disposal we were 

 unable exhaustively to search for fossils ; but, in a few instances, 

 evidences of their former existence in the deposit was established 

 by the presence of a few casts. Instead of showing clearly, as in 

 the section a few hundred yai'ds away, these remnants, too, 

 bore signs of considerable baking, which seems to be additional 

 evidence on the comparative ages of the greenstone and 

 Carboniferous sandstones. 



Some discussion has been going on, and diftei"ences of opinion 

 have been expressed, on this point. Gould, Strzelecki, and 

 Tenison- Woods considered that the greenstone was post-Carboni- 

 ferous. Jukes suggested the possibility of its being pre-Carboni- 

 ferous. Mr. R. M. Johnston maintained the latter view in his 

 " Geology of Tasmania." Professor David, in his presidential 

 address before the A.A.A.S. at Hobart, thought that the green- 

 stone was decidedly of later age than the Carboniferous and 

 Mesozoic rocks. Mr. Graham Officei", in a paper read before the 

 Royal Society of Tasmania last year, produced evidence that the 

 greenstone was post-Carboniferous. IMi*. Montgomery's observa- 

 tions also confirm this view. It is only fair to say that Mr. 

 Johnston has n^.odified his views, and now considers, with most 

 other observers, that the greenstone is post-Carboniferous, 

 although he has not yet published this opinion. 



The difficulty in deciding tliis question has always been to 

 obtain the point of contact ; a difficulty caused principally by 

 the disintegration and subsequent falling of the greenstone 

 columns, which generally obscure the line of junction. In this 

 section, however, although the actual point of contact is not 

 exposed, the sandstone is observed at a distance of only a few 

 yards from the vertical greenstone columns, and as the former 

 bears unmistakable evidence of having been subjected to a con- 

 siderable amount of heat, the inference is that the greenstone 



