13. REPORT ON THE RAPID SURVEY OF AN AREA IN THE 
BERWICK-CRANBOURNE DISTRICT. 
(By A. E. Kitson , F. G.S .) 
In 1854 and 1855 Dr. A. R. C. Selwyn* made a general geological survey 
of portion of the basin of the River Yarra, the Mornington Peninsula, and 
part of the country draining into Western Port. 
In the Berwick-Cranbourne district he marked a strip of basalt run¬ 
ning southwards from Berwick, all the country round Cranbourne being 
coloured as Tertiary. Nothing further in the way of a survey appears 
to have been done in the district until early in 1900, when, on noting 
from the train an occurrence of basalt near Cranbourne railway station, 
I was instructed to make a rapid survey of the locality. This led to 
the examination of the surrounding country, whenever a day was avail¬ 
able, on three occasions when passing through it, and it was found that 
the basalt covered a considerable portion of the parish of Cranbourne. 
It may be mentioned that Mr. R. A. F. Murray, F.G.S., has recorded! 
Cranbourne as a locality where “ older basalt” occurs, hut beyond the 
record nothing is given. 
The country here described is interesting, inasmuch as it possesses 
features which tend to throw some light upon certain geological difficulties 
that are.met with in the coastal sections on Port Phillip, between Franks- 
ton and Mornington. 
The formations noted comprise sandstones, mudstones, and claystones 
of Silurian age ; plutonic rock resembling granite, of probably Post 
Silurian age; breccia-conglomerate, leaf-hearing clays and sandy clays, 
probably Eocene; “older basalt” (Eocene?); a series of gravels, sands, 
grits, and clays, some of them ferruginous,'and containing casts of Eocene (?) 
shells in ferruginous clay; lastly, alluvium, drift-sand, and humus of 
Post Pliocene age. The term “Silurian” is used in a general sense, and 
not as the equivalent of the division “Upper Silurian" of the Survey, as 
no fossils have been recorded from the district. It is probable, however, 
that the beds really do belong to the Silurian, and not to the Ordovician, 
period. 
Silurian. 
The rocks of this age are, with two exceptions, found either near Ber¬ 
wick, on the Bairnsdale railway, or towards Langwarrin, on the south 
of the Cranbourne-Tooradin road. In the former case they occur as low 
spurs running from the Narre Warren ranges across the railway and 
terminating short distances south of it; in the latter they extend in a north¬ 
easterly direction from Mount Eliza through the parish of Langwarrin. On 
the Melbourne to Sale road, near Narre Warren township, the Silurians are 
first seen in the road cuttings, and thence to Berwick they are continually 
in evidence on all the low rises. They are chiefly yellow, grey and brown 
claystones, and fine argillaceous and arenaceous sandstones. About three- 
quarters of a mile west of Berwick they dip S. 30° E. at 38°, are fissile, 
* Selwyn, Geological Surveyor’s Report, with Plans and Sections. Papers presented 
to the Legislative Council, 1854. Report of the Geological Surveyor on the Geological Struc¬ 
ture of the Basin of the River Yarra, and Part of the Northern, North-Eastern, and Eastern 
Drainage of Western Port Bay, with Plans and Sections. Papers presented to Legislative 
Council, 1856. 
t Murray, Geology and Physical Geography of Victoria, p. 93. 
