146 THE VICTORIAN NATURALIST. 



at about the same level, suggesting, what is no doubt the true 

 explanation, that they are the remains of a former plain, which 

 has been broken into hills and hollows by the action of water. 

 A few trees grow on the table-lands, but on the hillsides scarcely 

 a tree or bush of any kind is to be seen, the ground being clothed 

 instead with the most luxuriant herbage, the source of untold 

 wealth to the sheep-farmers who own the land. 



Geologically, the district consists of mesozoic strata, overlain 

 on the table-lands and on the upper slopes of the hills by a thin 

 coating of ironstone gravel, of probably pliocene age. The 

 gravel must at one time have extended over a much wider area, 

 it having formed, no doubt, the original surface of the pliocene 

 plain, when the present isolated table-lands were continuous, and 

 before the existing valleys were marked out. As the ironstone 

 has evidently been precipitated from water holding iron salts in 

 solution, I think it likely that, in pliocene times, a great part of 

 the country was covered by swamps and marshes. The same 

 kind of ironstone is, in fact, still in process of formation in the 

 swampy ground to the west and north-west of the Glenelg River. 



The mesozoic strata comprise silicious shales and limestones of 

 a somewhat friable nature, which when laid bare become rapidly 

 disintegrated. Any creek or stream, therefore, that manages to 

 cut through the overlying ironstone, and thus reaches the lower 

 beds, soon carves out for itself a deep channel, which, in such 

 soft strata, gradually becomes a wider and wider depression in 

 the surface of the country. The denudation of these rocks, 

 caused by running streams and by the action of the atmosphere, 

 is, even now, very great ; and if we admit, as there are good 

 grounds for doing, that the rainfall of Victoria was, during the 

 pleistocene period, much heavier than at present, there is no 

 difiiculty in accounting for the rounded hills and sloping valleys 

 which are such marked features of the Wannon region. 



The nature of the formations being thus given, I will relate 

 how the shells occur. 



At the time of my visit to Coleraine, I was so busy that I 

 could only spare a few hours in the early morning, and Mr. W. 

 Trainor, the proprietor of the hotel, kindly undertook to drive 

 me to the fossil beds before breakfast. A start was accordingly 

 made at 6 a.m. the next morning, Mr. Skinner, the original finder 

 of the shells, accompanying us as guide. After going about two 

 miles and a half, a halt was called, the horses were unharnessed, 

 and we walked across a paddock, through thick, tall grass, which, 

 being covered with dew, soon made our feet soaking wet. 



Our road had brought us across the elevated table-land to the 

 south of Coleraine, and we had only begun the descent on the 

 other side when we stopped. Mr. Skinner now led the way to a 

 small hill, or rather mound, and commenced removing the surface 



