GLACIAL GEOLOGY OF COTMADAI. 
32S 
glacial character of the rocks under discussion ; but, as will have been 
observed, he had given us no intimation of any desire to publish any- 
thing on the subject. 
A great deal of Messrs. Sweet and Brittlebank’s paper is occupied 
in criticising our former contention that there was a Tertiary boulder- 
clav, as well as the much older one. It is true that we did originally 
maintain the presence of a Tertiary boulder-clay. Subsequently, how- 
ever, we became convinced of our error — -which had arisen through our 
mistaking redistributed glacial material for the rock in situ — -and we' 
hastened to correct it in a second note read before the Royal Society 
of Victoria in June, 1893, in which we gave our reasons for altering 
our opinion. Mr. Sweet was present at this meeting, and took part in 
the discussion. Under these circumstances it appears to us that 
Messrs. Sweet and Brittlebank’s criticisms were wholly unnecessary. 
6.— THE GLACIAL GEOLOGY OF COIMADAI. 
By GRAHAM OFFICER , B.Sc. ; LEWIS BALFOUR , B.A. ; and EVELYN G. 
HOGG , MJL. 
The principal locality referred to in the following paper is that 
of Coimadai, in the parish of Merrimu, and included between the 
Lerderderg Ranges on the west, Djerriwarrah on the east, the Lerder- 
derg River on the south, and running north from the Lerderderg 
about six miles. This country lies to the east and north-east of that 
described by Messrs. Sweet and Britt! ebank in a paper read before the 
Association at its Adelaide meeting. 
We became first acquainted with Coimadai about eighteen months 
ago, when we made certain discoveries that decided us to commence a 
systematic investigation of the geology of the district. This we have 
since been attempting to carry out. 
In the present paper we shall deal only with the glacial deposits 
developed in the district, and shall refer to other deposits in so far 
only as they bear on the strati graphical relationships of the former. 
PHYSICAL FEATURES. 
The country is traversed hv the Lerderderg River and its tribu- 
taries, the Goodman’s, Fyrete, and Djerriwarrah Creeks, all of which 
flow in a southerly direction. Back and Basin Creeks flow respec- 
tively into Goodman’s and Pyrete Creeks. The area of this district is 
about 36 square miles, of which the glacial beds appearing at the 
surface occupy a small proportion. The interest in this locality lies 
to a large extent in the remarkable sections exposed on certain of the 
streams traversing the country. 
The physical aspect of the country presents certain well-markedi 
features dependent on its geological structure. The formations 
present in the district are — 
Lower Silurian, 
Glacial Series, 
Tertiary, 
Basalt, 
Recent. 
