GLACIAL GEOLOGY OF COIMADAI. 
325 
contains numerous scored and glaciated pebbles and boulders scattered 
irregularly through the matrix. Well-stratified bands occur here and 
there, as well as irregular patches of grit and conglomerate. Pine 
sections of this are to be seen on Grood man’s Creek, one mile above 
Elam’s, on the Lerderderg Fiver, and on the Pyrete Creek. On Good- 
man’s Creek this conglomerate lies over the stratified clays. 
(3.) Stratified Sandstones and Freestones. 
The third class of beds are the sandstones. They are developed 
in this district only between the Lerderderg and Goodman’s Creek. 
We have not observed any on the side of the Pyrete Creek. They are 
quite similar in appearance to the Bacchus Marsh sandstones, and 
have been quarried for building stone. They contain intercalated beds 
of mudstone and conglomerate, and are often highly calcareous, and 
generally contain magnesia. Here and there large boulders of granite 
and other material are met with in these sandstones, one such 
measuring 4 feet in diameter. 
THICKNESS. 
The thickness of rock exposed in the Coimadai district is not 
nearly so great as on the Korkuperrimul Creek, and given by Messrs. 
Sweet and Brittlebank as 4,000 feet at least. The sandstones on 
Goodman’s Creek are probably not more than 100 feet thick. They 
probably lie below the Bald Hill sandstones. 
The average angle of dip is much smaller in Goodman’s and 
Pyrete Creeks than on the Korkuperrimul, the beds showing com- 
paratively little disturbance. Faults of a few feet are not uncommon, 
but so far we have not detected any of large size. The average angle of 
dip along Goodman’s Creek is not more than from 12° to 15°. Near the 
south end of the cieek, on the Lerderderg Fiver, the beds are dipping 
about 20° to 25° 8., 20° E., corresponding to the general dip of the beds 
in tlie region treated of by Messrs. Sweet and Brittlebank. North of 
this, between this point and the termination of the beds against the 
Silurian, two anticlines are developed, which are probably of only 
minor importance. Measuring along one leg of one of these anticlines, 
taking an average angle of 12°, we get a thickness of about 1,200 
feet ; and adding the thickness of the beds not shown in this anticline 
we arrive at a total thickness of 1,800 feet. 
The glacial beds are much jointed, but two sets can be dis- 
tinguished, the most constant having a direction approximately E. and 
W., while another set has a general N. and 8. direction. Dykes are 
numerous, and seem to have followed the direction of the E. and W. 
joint planes. Sections of these have been prepared for microscopic 
examination. 
ROCK MATERIAL. 
This is very varied. Much is similar to that found in the Bacchus 
Marsh district, but we found specimens that we do not remember 
having seen elsewhere. Sections of much of this material have been 
prepared for microscopic examination, and the results will be published 
in a future paper. Granites are very abundant, the largest boulders 
being of this material. Quartz, quartzites, quartz-porphyry, sand- 
stones, jasper, lydianstone, gneiss, slates, conglomerate also occur in 
the drift of this district. The quartzites as a rule exhibit the best 
scorings and groovings. 
