THE VICTORIAN NATURALIST. 83 



which has probably taken place since the impressions were 

 made, Mr. Officer is of opinion that a considerable lapse of time 

 has occurred since the rocks were laid down, and he suggests 

 that the impressions were made by two individuals sitting close 

 together and somewhat obliquely to each other. 



In the discussion which followed, Mr. D. M'Alpine, F.C.S., 

 spoke in complimentary terms of the paper, and referred to the 

 action of carbonate of lime in the preservation of such marks, 

 whilst Mr. F. R. Godfrey, who had seen the slab, bore testimony 

 to the remarkable similarity of the impression to human footprints. 



Mr. J. Dennant, F.G.S., F.C.S., remarked that as his authority 

 had been quoted for the recent age of the u^olian rocks, he would 

 state the argument for that view. The newer basalt, which 

 underlies these rocks at Portland and elsewhere, must itself be a 

 comparatively modern deposit, for it is younger than the late 

 pliocene beds at Limestone Creek, about 25 miles inland from 

 the Glenelg mouth. Unlike igneous or unfossiHferous sedi- 

 mentary strata, there can be no doubt about the age of the 

 Limestone Creek beds, as they have yielded nearly 250 

 species of marine shells, 81 per cent, of which are still 

 living in our seas. The order of strata then is : — Marine 

 Later Phocene of Limestone Creek ; Newer Basalt of Port- 

 land, &c. ; and on the top of this the yEolian rocks. 

 The basalt, from its superior position with reference to the marine 

 beds, must be classed as pleistocene, and as a consequence the 

 still younger .^olian rocks could only have been deposited either 

 at the close of the pleistocene or at the commencement of the 

 recent period. In the absence or extreme paucity of fossils in 

 the last-named deposit, there is insufficient data for deciding be- 

 tween the two alternatives. I incline to regard the rocks as 

 recent, because they are still in course of formation. The very 

 best locaUty for observing this is amongst the sand dunes of 

 Bridgewater and Discovery Bays, where the material may be seen 

 in every stage, from loose sand to consolidated rock, almost as 

 hard as that used for building purposes at Warrnambool. Tenison 

 Woods studied the ^olian rocks of Victoria and South Australia, 

 and described them most graphically in his " Geological Obser- 

 vations in South Australia," published in 1862, but as he entirely 

 altered his opinions concerning the mode of their formation in his 

 later years, the age assigned to the strata in that work need not 

 be taken into account. No information is to hand as to whether 

 the rock is found on the islands lying between Tasmania and 

 Victoria, and in any future excursion of the Club to these islands 

 the geological members of the party might be asked to note 

 whether it exists, and, if so, its elevation above sea level. Some 

 clue might thus be obtained as to an alleged subsidence of the 

 land since the consolidation of the earlier dunes. The author of 



