BY L. A. COTTON. 829 



tion ill the dolerite, it is common to find in it fragments of quartz, 

 which have undoubtedly been derived from the granite. The micro- 

 scopic examination reveals the presence of a very small amount of 

 free quartz, but this appears to have crystallised from solution, 

 and not to be of an included nature. 



The small neck at Staggy Creek, is composed of practically the 

 same rock. As the localities are distant about four miles, it is 

 probable that the magma, from which the rocks were formed, was 

 of some considerable extent. This neck also intrudes the granite- 

 mass, and no sedimentary rocks occur within some 4 or 5 miles of 

 either occurrence. It must be noted that, in each case, diamond- 

 bearing river-gTavels of later age have been found overlying the 

 dolerite-masses. 



Xot only is this so, but, in the case of one of these, it has been 

 amply demonstrated that a diamond was found fast embedded 

 in the dolerite-matrix. The specimen has been preserved, and 

 has been shown to many eminent geologists by Prof. T. W. E. 

 David, wlio writes* as follows : — "At the meeting of the British 

 Association at York, England, as well as that of the Inter- 

 national Geological Congress of Mexico last September, this speci- 

 men was most critically examined by the chief scientific authori- 

 ties on diamonds in the world, and all were satisfied as to the 

 absolute genuineness of the discovery, and considered it of the 

 highest possible scientific interest. " A second diamond was also 

 exhibited with the one embedded in matrix. This was stated to 

 have been found free in the heap of decomposed dolerite. It 

 was agreed, by scientific observers, that this was even better 

 evidence of the genuineness of the discovery, from the fact that 

 the diamond was pitted, and that the pits were filled with finely 

 crystallised dolerite, evidently in situ. 



Having examined both the above-mentioned specimens, and 

 the spot where they were found, I also feel quite convinced of 

 the genuineness of the discovery. 



Active interest was aroused in 1912, and about 100 tons of 

 the dolerite were mined and exposed to the weather. Shortly 



• Prof. T. W. E. David, Sydaey Morning Herald, 19th and 26th Jan- 

 uary, 1907. 



