12 AISTNIVEESAET ADDEESS. 



Certainly, tlien, if there are no carboniferous rocks in BaBia, 

 -tlie suggestion of Mr. IN'orman Taylor, referred to by me in 1870, 

 as to tiie possibility of the diamonds at Cudgegong resulting from 

 the carbon derived from such rocks, must go for little. Another 

 suggestion has been offered, riz., that carbonic acid gas of recent 

 times has been in reqxiisition. But since Mr. Hartt rejects an 

 Itacblumite origin all througli Brazil, Ave are driven nearer and 

 nearer to a tertiary source. 



"I do not believe," he says, " that the diamond ever occurs in 

 true Itacolumite in Brazil, but that it is derived from tertiary 

 sandstones." Capt. Burton, on the other hand, maintains the 

 opinion that Itacolumite is a matrix of diamond ; and mentions 

 one sent by him to England imbedded in that rock. 



It is probable, therefore, that in Australia, river-drifts, formed 

 from various deposits, may be the present derivative sources of 

 supply. 



Since the question was first mooted, I have been on the look- 

 out for fresh localities in addition to those already known. I 

 can now add to our former scanty list of diamond sites, one near 

 the Horton Eiver, having examined specimens collected there ; 

 and another from a portion of the Macquarie Eiver, a long way 

 above Suttor's Bar, and only a few miles below Bathurst, from 

 which spot diamonds were shown to me in that city in April last, 

 A third locality is near the head of the Eish Eiver, which is, in 

 fact, the Macquarie ; so, tliat river is at intervals diamond-bearing 

 for many miles, as from the neighbourhood of Oberon to Burren- 

 dong it cannot be less (in crow-fly distance) than 90 miles. These 

 new sites raise the number of localities in Australia to twelve, of 

 which two belong to South Australia, and five each to New South 

 "Wales and Victoria. 



There may, doubtless, be many more ; but of a tertiary sand- 

 stone, resembling that of Bahia, I have seen nothing in Australia, 

 where also Itacolumite is not known to exist. Such negative 

 testimony may not be worth very much, but it has its value not- 

 withstanding ; it may point to other sources than those yet knovrn. 



