1872.] DAINTREE GEOLOGY OF QUEENSLAND. 309 



probably a dyke, but exhibiting no traceable outcrop. It is in a 

 loose rubbly condition, and is exposed in a somewhat abrupt face on 

 one side of a broad gully runniag into Sandy Creek, a tributary of 

 Barambah Creek. Infiltrations of green and blue carbonate of 

 copper form thin films and coatings on the numerous surfaces pro- 

 duced by disintegration of the rock ; and oxide of iron now fills the 

 cavities once occupied by crystals of pyrites. Both the copper and 

 the gold have doubtless been derived from the decomposition of 

 auriferous pyrites, which appear to have been developed sporadically 

 through the mass, and not collected into veins." 



Taking, then, the case of " Green's reef " and the " Tunnel 

 claim " to prove the occurrence of gold per se in group 4, the Ban 

 Ban and Cumming's so-called " reef" would be parallel cases for 

 group 1. 



The Canoona Diggings would seem to afibrd the best evidence of 

 gold occurring in situ in serpentine. Here a gully has been worked 

 from its head for three quarters of a mile down its course, the bed- 

 rock being serpentine only, the wash-dirt a brown serpentine clay. 

 When the gold was found with the matrix attached, that matrix 

 was serpentine. The "puddlers" in this gully have been continuing 

 their operations for years. After washing and rewashing the clay 

 detritus, they now take a little more of the decomposed undrifted 

 serpentine, and from this source still obtain a bare subsistence, with 

 sometimes, as they say, a " little find." 



The case of " Block's claim," under Mount "Wheeler, may be due 

 to hydrothermal action attending the intrusion of the felsite of the 

 Mount ; and the gold cannot, therefore, be assumed as originally 

 present in the serpentine. 



Of 'No. 2 (the diabase and diorite group), from individual expe- 

 rience we can make no assertion as to the presence of gold through 

 the mass of the rock, since a large collection of pyrites obtained 

 from various auriferous districts in Queensland, which were intended 

 for assay, was found to be distributed throughout the case con- 

 taining them, when this case was fished up from the wreck of the 

 'Queen of the Thames;' the specimens were therefore useless for 

 the purposes for which they were collected. 



The evidence of Mr. Aplin, the late Government Geologist for 

 Southern Queensland, as bearing on this point, may, however, be 

 adduced. Speaking of the Gooroomjam diggings, he says : — 



" Gooroomjam is situated on that portion of the Bunya range 

 which divides the sources of the Brisbane river from those of the 

 Burnett. 



" The diggings are confined to two guUies that descend from, 

 either side of the range. 



" The one is worked for about a mile and a half in length ; the 

 latter for even a less distance than this. Both are nearly worked 

 out ; and there is little probability of a further extension of either. 



" The area mined on consists entirely of greenstone, with the 

 exception of the lower portion of the workings on Monarumbi Creek, 

 a mile or so below the lower township, where massive hornblendic 



