On tlie Occii,rrence of the Diamond, near Mudgee. 99 



the consolidation is the result of infiltration of manganese and 

 iron oxides, in whicli case the colour is black or brown. 



Diamonds have been picked out of the loose material, and, by a 

 special experiment, which Mr. Taylor conducted, they have been 

 proved to exist in the consolidated portions. Kve bags of the 

 conglomerate, weighing seven or eighb hundredweight, were 

 burned, crushed, and subsequently washed, and yielded two 

 diamonds and three-quarters of a pennyweight of gold. The 

 diamonds do not appear to be confined to any particular level in 

 the drift deposit, though the lower parts are in preference taken 

 by the miners, probably in consequence of the certainty of 

 finding gold in this portion. The mere fact of the not unfrequent 

 discovery of diamonds on the waste heaps round the old shafts 

 that were sunk for gold, is enough to suggest that the diamond 

 may occur in the higher portions of the deposit, since the bottom 

 layer has been invariably carted to the river for gold washing. 

 One diamond which was observed in situ occurred three feet from 

 the bottom, imbedded in a mass of loose quartz pebbles, about 

 the size of peas. Huge blocks of hard slate, sandstone, quartz, 

 greenstone, and felspathic rock, the two latter often wasted into 

 masses of clay retaining the original shape of the boulders, lie at 

 the base of the drift in many parts. The drift varies much in 

 character, but is chiefly made up of boulders and pebbles of 

 quartz, jasper, inferior agates, quartzite, hard flinty slate, shale, 

 and sandstone, with abundance of coarse sand, and more or less 

 clay. The quartz pebbles are milk-white like vein quartz, but 

 are generally encrusted with a thin film of iron oxide, either 

 brown or pinkish. Manganese is abundant, both cementing the 

 drift in irregular patches, and coating pebbles with a black crust 

 or dendritic markings, or, as if smoked, soiling the fingers when 

 rubbed. Some of the boulders and pebbles are coated all over 

 with a remarkable brilliant siliceous polish, which cannot be the 

 result of friction, as the concave surfaces and irregularities are 

 just as highly polished as the more exposed parts; it is most 

 probably the result of infiltration of silica, and is analogous to 

 the coatings of iron and manganese. 



Water-worn boulders of silicified wood frequently occur in the 

 drift ; they precisely resemble the fossil wood which is so 

 abundant in the coal formation of New South Wales, and have 

 probably come from the waste of similar Carboniferous rocks to 

 those which now occur in the neighbourhood of Wialdra Creek, 

 or form the escarpments which follow the N.E. side of the river 

 basin, and completely surround its head waters. Silicified wood 

 from these sources is found in the present river-bed. Coal has 

 been seen in the older drift, higher up the river. 



Other relics of fossiliferous deposits have been found more 

 sparingly. These comprise several large rolled pebbles of the 



