in South-Western Victoria. 243 



waters were unable to wear away. These broad flats have 

 thus been formed, partly by the river, and partly by the sea 

 itself, which had access to the estuary, and the shells which 

 were so plentifully strewn on sheltered places under the 

 river cliffs have been since cemented together, more or less 

 completely, sometimes forming a hard rock, and at others a 

 very friable one. In some cases, blocks of the ancient lime- 

 stone, thrown down from the cliffs, have been encrusted with 

 the shells, which adhere firml\^ to them. It is not easy 

 always to distinguish between the two rocks, unless a close 

 examination is made, when the older one is seen to contain 

 its characteristic fossils, corals, bryozoa, &c., while in the 

 newer these are, of course, wholly wanting. 



The Bankivia beds were most probably laid down during 

 the upheaval, which has raised the whole of the south coast 

 of Victoria, a period of rest occurring while the upper terrace 

 was being formed. Although, as said just now, the great 

 width of the flats here must be in a great measure due to 

 sea action, they were, no doubt, first shaped out by the 

 river itself, as flats of tolerable size are found almost to 

 its source, and amongst very varying strata, a wide excava- 

 tion having been made in the upper part of its course 

 through slate, sandstone, and even granite. It is most 

 significant that the flats diminish in extent to the 

 south of Limestone Creek, and soon cease altogether, the 

 gorge narrowing so much that for the last 70 or 80 miles of 

 the river's course the opposite banks are seldom more than 

 800 or 400 yards apart, while the successive terraces no 

 longer appear, the cliffs rising directl}^ from the water's edge. 

 In no part of the river are the banks so widely separated 

 as in the neighbourhood of Limestone Creek. Here, I 

 believe, the mouth of the Glenelg remained for a long 

 period, enabling a vast accumulation of littoral shells to take 

 place. As the land rose, the estuarine deposit was gradually 

 removed farther and farther from the coast, while the river 

 has, in the course of time, cut a winding channel through 

 the flats, and through the ancient limestone farther south, as 

 this gradually emerged from the bed of the ocean. 



r2 



