ON CERTAIN BOULDERS OF THE GYMPIE GOLD-FIELDS. 299 



should, however, state that I have not found a single instance of 

 the boulders being grooved or striated, they are usually rounded 

 and smooth. 



The only other explanation, I can see, that would account for 

 their occurrence, is that tliey may have fallen from the roots of 

 floating trees. 



A granite boulder was found on the foot-wall of the O'Connell 

 Reef in the O'Connell Prospecting Claim at a depth of two 

 hundred and forty feet. A portion of the boulder was given 

 to me, and its position described by the manager, who was present 

 when it was taken out. 



The stone consists of a coarse-grained pink granite, composed 

 of pink orthoclase, large clear blocks of quartz, and a little decom- 

 posed mica. Judging from the curve of the fragment in my 

 possession, the boulder must have been at least seven and a-half 

 inches in diameter ; it was smooth and rounded. This is the only 

 instance of a granite rock being found anywhere in the neighbour- 

 hood of the field. The nearest granite, m si'iw, to my knowleds^e, 

 is that of the Black Snake Range, situated about twenty miles 

 west of Gympie ; the boulder, however, has probably ti'avelled 

 a greater distance than that, as the granite of the range is 

 difi'erent in character to that of which the boulder is composed. 



The question arises, how did it come into that position ? In the 

 first place, the fissure of the reef must have remained open, for 

 some time, sufiiciently to allow of the introduction of a stone of 

 that size down to the depth at which it was found (240 feet). It 

 would appear, too, that the land at the time must have been sub- 

 merged, for had it been conveyed there by a land stream, the open 

 fissure in the reef would have been entirely filled with boulders 

 and silt carried along by it. I therefore have come to the conclu- 

 sion that it was conveyed, and dropped, probably, from floating- 

 ice, into its position, and while perhaps other blocks of similar 

 rock wei'e dropped on to the floor of the sea, and have since been 

 removed by denudation (which the presence of large faults on the 

 field shews it must haxe been very great), this one which happened 

 to enter the fissure has been preserved. 



Mr. Jack in his Report on the Bowen River Coalfield speaks of 

 the occurrence of large isolated boulders of granite, itc, in the 

 midst of strata composed of fine sandy or muddy material, for 

 which he can see no other explanation than floating-ice ; and it is 

 possible that this boulder may have been deposited at the time 

 the coast country was submerged, and that the Bowen River, 

 Burrum, and the other Palaeozoic Coal Measures were being 

 formed. 



