THE GEELONG NATURALIST. X 
GEOLOGICAL NOTES 
ON THE ROAD TO BIRREGURRA. 
By J. F. MULDER. 
THE country between Geelong and Mount Moriac appears to 
have,been in or about the Post Pliocene; a series of fresh 
water lakes evidently existed. “These lakes have been partly 
filled up by streams of volcanic rock, probably from some of 
the mounts in the district (Moriac and Duneed); the 
boundaries of these lakes appear to have been the old 
Mesozoic formations of the Barrabool hills and Cape Otway 
ranges. When near Mount Moriac the soil improves to a 
rich loam, probably caused by the decomposition of the 
masses of Basalt surrounding the Mount ; after passing some 
miles beyond, the soil assumes its original character, and 
although more undulating, a great portion is composed of 
gravel and grit, alternately with volcanic soil moderately rich, 
but shallow, the subsoil being a poor sandy clay. As we 
pass on westerly the country is composed of rich alluvial flats, 
the aforesaid basalt cropping up in all directions. After 
passing Winchelsea the principle object of interest which 
attracts the student of Geology is a peculiar bank stretching 
for miles and running parallel under the Cape Otway ranges. 
These banks are from thirty to fifty feet above the flats lying 
between them and the ranges; they seem to have been formed 
by the sudden arresting of thé stream of basalt, which about 
that time flowed over the face of the country. There must 
have been about this time an immense fresh water lake, or 
probably a river, with low lying delta stretching for miles 
between the old Mesozoic formation of the Cape Otway 
ranges and these basalt ridges, for the whole country between 
the two. consists of gravel, sand beds, and fresh water clays, 
red, white and yellow; this lake or river appears to have 
existed for a considerable period, and the deposit as exposed by 
the railway cutting at Dean's Marsh, from forty to fifty feet 
deep, does not reach the bottom of the deposit. "These 
beautifully rich flats stretching along the foot of the basalt 
cliffs is, I believe, the delta of the old Barwon, which probably 
had a far different course than it has at present, besides being 
a much finer stream ; its course appears to have been along 
the foot of the ranges, from the direction of Warrnambool, 
very likely through swamps and low-lying country as in the 
case of the Connewarre lakes, and emptied itself in the direc- 
