132 ANTHRACITE IN A FISSURE LODE 



From a stratigraphical standpoint the indication that 

 these supposedly Silurian strata are coal measures is of 

 great interest ; but unfortunately the carbonaceous shales 

 rapidly disintegrate on exposure to the atmosphere, render- 

 ing search for fossils in the material of the waste dumps 

 hopeless ; and we are consequently without palaeonto- 

 logical assistance in correlating them with the sedimentaries 

 outside of the district. Mr. Brown, the Government 

 Geologist of South Australia, has, it may be mentioned, 

 referred* the carbonaceous shales of the McArthur River, 

 which may be an extension of the Queensland area, to the 

 Permo-carboniferous system, on account of their resem- 

 blance to the productive coal measures on the north-western 

 coast of the Northern Territory. Further field Avork 

 in this quarter of Australia is thus likely to have very 

 interesting results, and it may even yet be shown that the 

 strata belong to some of the older palaeozoic formations, 

 as Lower Silurian shales — black from diffused anthracite — 

 a.re not unknown in other parts of the world.f 



OCCURRENCE AND NATURE OF THE COAL. 



The lodes of this field are in general composite fissure 

 veins. The Silver King lode formation in particular has 

 a. width of over 60 ft., and, while looking into its capabilities 

 as a lead and zinc producer, I noticed in many parts the 

 gangue associated with crystalline blende and galena was 

 very dark in colour. Specimens were collected and subse- 

 quently examined in the laboratory, where pyrognostic 

 tests indicated the presence of carbonaceous matter, which 

 it may be taken was probably effective in precipitating 

 the sulphides of the ore body, although the average amount 

 of fixed carbon over the whole width of the formation does 

 not exceed 1 or 2 units per cent. Some of the less crushed 

 matrix having the physical characters of coal, a fragment 

 was handed to the Government Analyst, who found it 

 (when separated from the attached ore) to have the com- 

 position tabulated below. This result agrees fairly w^ell 

 with the partial analysis of an ordinary commercial 

 anthracite,J though the voh/ale matter is rather lower 



* Geological Reconnaissance from Van Diemen's Gulf to the McArthur 

 River, 1907. 



fSee Geikie's Text Book of Geology, 3rd Edition, p. 145. 

 JSee Economic Geology, Vol. 4, p. 657. 



