a ee TR, ee ee Oe Ne ee ee Cn eee a a pe ee re —_ 
_ GEOLOGICAL LABORATORY NOTES. 407 
The water contained traces of zinc and large quantities of 
“soluble” organic matter. The large percentage of sodium and 
chlorine opens up the question as to whence this sodium chloride 
—as it exists in the water—was derived. 
TV.—On tue TRACHYTES OF THE CANOBLAS AND THE WARRUM- 
BUNGLE MOoUNTAINS. 
The first reference to a trachyte from the Warrumbungle 
Mountains that I can find is a note by the writer.’ “This typical 
trachyte was described as coming from Timor rock, Subsequently 
a trachyte from the Coonabarabran district was described by Mr. 
G. W. Card.2- I do not know that any record has been made 
hitherto of a trachyte from the Canoblas near Orange. About 
six miles west of Coonabararan there is an isolated hill some eight 
to nine hundred feet in height. The weathering of the rocks on 
its sides is quite suggestive of the trachytes of the Drachenfels. 
The base of the hill is composed of a grey trachyte that in hand 
Specimens shows a mottled appearance. Under the microscope 
the rock shows an abundance of sanidine, and the mottling is due 
to aggregates of ‘‘ blue hornblende ” that abound in the rock. An 
exactly similar rock is found on the Canoblas near Orange, on the 
eastern slopes of the mountain above Mr. George Plowman’s farm. 
Both at Timor and on the Canoblas I have seen sufficient to con- 
vince me that these trachytes are older than the basalts and more 
basic lavas that abound in those districts. 
About half way up Timor the character of the trachyte changes. 
The rock is there of a dull green colour with a shade of yellow. 
Abundant needles of sanidine are seen glistening in the rock. 
The microscope shows a decided flow structure, and a constitution 
corresponding to a typical trachyte. 
About ten miles to the north of Coonabarabran there is a hill 
of a compact trachyte that breaks with a fracture not unlike 
quartzite. Under the microscope the rock shows as composed 
Proceedings Linnean Society, N. 8. Wales, Vol. 1x., p- 467, Series 2. 
2 Records of the Geological Survey of N. S. Wales, Vol. 1v., p- 115, pl. x- 
