448 PROCEEDINGS OF SECTION C. 
that they were left by a retiring sea. Another explanation some- 
times given is that they are due to the action of Post-Miocene 
glaciers, which are supposed to have scooped out the hollows ; but 
as I have failed to discover any evidence for the former glaciation 
of the province, I regard the theory as untenable. In my 
opinion most of them are simply the remnants of former rivers, 
which have dried up owing to a diminished rainfall. On one 
occasion, when standing on the top of Mount Arapiles, it appeared 
to me that the lines of these ancient rivers could be fairly traced. 
As this mountain rises out of a plain, the whole country around 
is spread out before the eye, and many of the lakes, which dot the 
landscape, could easily be supposed to be merely chains of water- 
holes in the course of former streams, the channels between them 
having been choked up by sand. The country falls northwards, 
that is, towards the Murray, the watershed between that river 
and the Glenelg being a little to the south of Edenhope ; and I 
am told that, even yet, after an*’unusually heavy downpour, there 
is an actual current from Lake Wallace to Booroopki swamp. 
None of these lakes are deep, and many of them are for years 
together perfectly dry. In one instance, a small lake, near 
Apsley, was regarded as permanently dry, and a house was built 
by one of the early settlers in the middle of it. The succeeding 
winter proved, however, a wet one, and the lake was not only 
then filled, but has never been dry since. 
But to return to the strata of the Upper Tertiary. An 
exceedingly interesting deposit is found on the Glenelg, in the 
neighbourhood of Limestone Creek, and thus about 25 miles, in a 
direct line, from the coast. The river gorge is here very wide, 
and the beds now referred to lie just on the margin of the 
stream, at the foot of the cliffs, which consist as usual of Lower 
Tertiary rocks, overtopped by the Ostrea limestone. In describing 
them a few years ago,* a list of 141 fossils was given, but since 
then many additional species have been collected, the names as 
well as the distribution of which have been, with his usual kind- 
ness, supplied by Professor Tate. The material available for 
comparison has thus much increased, and a slight modification of 
the conclusions formerly arrived at will be necessary. Altogether, 
242 species are to hand, of which 212 are well identified, and the 
following remarks will apply to them only. The living species 
amount to 171, and the extinct ones to 41, so that the proportion 
of recent forms is about 81 per cent. In my previous paper a 
similar calculation gave a much higher percentage, but the 
number of determined species was then only 121, and it is a 
curious circumstance that the later collections include a much 
larger proportion of extinct species than the earlier ones. Of the 
extinct shells, 20 are peculiar to the Lower and 8 to the Middle 
* Trans. and Proc. Roy. Soc. Victoria, 1887, 
