200 
at this point, and also at the south-west boundary of the area, are com¬ 
posed of rounded and angular fragments, ranging up to several inches in 
diameter, and consisting principally of fragments of a porphyritic struc¬ 
ture, some having the appearance of Silurian fragments; these are em¬ 
bedded in a finer matrix. The tuffs shown to the west of Cement Creek 
are of a finer material. 
The Silurian slates, shales, and sandstones, do not appear to have been 
altered along the contact, except in a few localities where a granite mass 
is usually found in close proximity. In the bed of the Don River, a short 
distance from the saw-mill site, hard indurated Silurian sandstones are 
to be seen dipping to the west at an angle of about 25 deg. with the dacites 
on both sides of the river apparently overlying them. 
The Silurian strata in the vicinity of the granite bosses shown to the 
north of the Watts River are considerably indurated. 
In the Acheron valley the Silurian formation extends for about 4 miles 
to the south-east of: Narbethong, but I did not have an opportunity of 
filling in this contact. 
Several small granite bosses occur in close proximity to the dacites. 
One small patch lies on the east side of the Ligar River, and is intersected 
by the race cut for mining purposes. At Warburton a granite contact 
occurs, and another to the south-west of the area in the parish of Grace- 
dale. To the north of the Watts River are shown portions of two small 
bosses, one of which has been described by Mr. Selwyn on his sketch plan 
as a hornblendic granite passing into a porphyry towards Mt. Monda. The 
second mass is shown to the west of Meyer's Creek, and extends in a 
westerly direction towards the New Chum Creek, and has not been pre¬ 
viously noted on any of the geological plans. A much larger area of 
granite exists to the north in the watershed of the Murrundindi Creek, but 
owing to the extremelv rough and inaccessible nature of this country, no 
information is obtainable. An examination of the ranges towards the 
heads of Britannia Creek, to the south of Warburton, failed to reveal any 
dacite. The rock all appears to be granite. 
The soil formed by the decomposition of the dacites is generally of a 
rich chocolate colour, and is in many places of considerable depth. It 
supports a dense and luxuriant flora, consisting of mountain ash, gums, 
wattles, musk, blackwood, native beech, sassafras, dogwood, ferns, and a 
•varied assortment of small shrubs. 
In conclusion I beg to state that, in my opinioin, the evidence so far 
obtained, tends to support Professor Gregory's opinion, that this mass 
is the result of volcanic origin. 
Owing to the total absence of any more recent geological formations 
in the locality, it is impossible at present to form any idea of the age of 
the dacites, except that they are post Silurian. 
\Report sent in 16.10.0j .] 
DIAMOND DRILL BORING IN SEARCH OF SADDLE REEFS. 
By E. J. Dunn , F.G.S., Director , Geological Survey. 
The experiment of boring on the anticline in search of saddle reefs, as 
carried out on Mr Hilhs lease at Bendigo, has clearly established the suit¬ 
ability of this method of prospecting. 
In carrying out such work it is necessary to take certain precautions 
and to have a grasp of the rock structure at the proposed site. The ideal 
site for boring in search of saddle reefs along an anticline (centre country),. 
