GLACIAL ACTION—VICTORIA. 361 
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glacial origin is exposed. It is very limited in area, being about 
30 yards long ; it occupies the whole width of the stream. At its 
eastern extremity it is seen resting on the upturned edges of the 
gneiss, which constitutes the bed-rock in this locality ; its western 
boundary is a mass of igneous rock, which on microscopic examina- 
tion is found to consist almost entirely of sanidine. 
The actual junction of the two beds is unfortunately masked by 
alluvium and sand ; owing to the amount of water in the river at 
the time I visited it any excavation to determine whether the clay 
was altered at the junction was out of the question. The bed 
consists of a light-brown and yellowish tough clay, through which 
small stones and boulders are somewhat scantily distributed. 
Most of the bed being under water, it could not be properly 
searched, but in addition to two well-marked striated stones I 
secured small boulders of ternary granite, quartz, quartzite, sand- 
stone, and mica-schist. The sanidine rock was not found in the 
clay. The outcrop, though small, is interesting, as showing the 
northerly extension of the glacial beds of the Coleraine area, of 
which it must be I think regarded as an outlier. It may also 
afford a clue to the age of the igneous rocks which offer a problem 
of great complexity in this district. 
No. 2.— FURTHER EVIDENCE AS TO THE GLACIAL 
ACTION IN THE BACCHUS MARSH DISTRICT, 
VICTORIA. 
By C. C. BritrLeBank, GeorcE Sweet, F.G,S., and Proressor 
T. W. EpcewortH Davip, B.A., F.G.S. 
(Read Monday, January 10, 1898.) 
RELATION OF MATRIX AND BOULDERS TO LOCAL ROCKS. 
WISsHING to ascertain, if possible, the true nature of the Bacchus 
Marsh glacial deposits, some considerable attention has been paid 
to the relation of the boulders and matrix forming the glacial beds 
to the local rocks. This investigation was undertaken for the 
express purpose of discovering (a) If the Bacchus Marsh glacial 
-deposits were a true till. (6) If of marine or fresh-water origin. 
Mr. 8. J. B. Skertchly says [evidently with the approval of 
Professor J. Geikie]: “There is a remarkable modification of the 
law that physical character of the boulder clay is dependent upon 
that of the subjacent rocks, a modification which evidently cannot 
be explained on the marine theory, nor yet on that of local 
glaciers. This is the invasion of the outcrop of one rock by the 
