THE VICTORIAN NATURALIST, 173 



• — being in small proportion. Dense dark sandstones, with silvery 

 flakes of mica, spotted and mottled schists, occur, as well as a 

 whole series of silicas. Mr. Hollingsvvorth's collection comprised 

 lydianite, opal, jasper, chalcedony, and chert, as well as a 

 beautiful specimen of mica schist and a mass of the siliceous 

 breccia, which occurs, I believe, in situ, in the silurian rocks near 

 Heathcote. Besides these, there is an almost endless variety of 

 other rock, and I do not remember ever seeing before such a 

 variety gathered in such a small area. To the north and east of 

 the Derrinal railway station the deposit forms steep hills over- 

 looking the creek valley. These hills are covered with masses of 

 rock of all sizes. One mass of granite was measured by Mr. 

 Craig and estimated to weigh about forty tons. The block is 

 rectangular in form, and is referred to in Mr. Dunn's paper (I.e.) 

 It is ground on several faces ; but the top, as it at present lies, 

 which measures 12 ft. x 14 ft., is flattened and smoothed in a very 

 striking manner. The granite, which contains pink felspar, is very 

 coarsely grained. Around it lie numerous other fragments of smaller 

 size, and of various kinds of rock, and almost all show evidence 

 of ice action, either as striations or as well-ground facets. The 

 land above forms a plateau and has been ploughed. It is thickly 

 strewn with rocks, which have been gathered into heaps in 

 places, and afford good opportunities for collecting. In the 

 creek bed, which is about a hundred feet below the plateau, the 

 dark grey deposit is exposed in places where the river gravels 

 have been removed. How far below this the beds extend 

 vertically, I cannot say. Time forbade our visiting some of the 

 locahties we wished, and we did not attempt to trace the 

 boundaries of the deposit nor study its relations for ourselves. 

 It is stated to occupy a basin in the silurian rocks, and its age 

 has long been a matter of conjecture, though it is older than the 

 Bacchus Marsh sandstones. There is a geologicnl survey party 

 in the neighbourhood, and doubtless they will give some of their 

 time to these beds. Mr. Dunn refers the age to the Trias, as he 

 considers them comparable to the Dwyka beds of South Africa, 

 which underlie fresh-water coal-bearing beds. 



Though doubt has been thrown on the glacial origin of these 

 beds by able geologists, both in years gone by and, more 

 recently, at the Melbourne meeting of the Australian Association, 

 no one, I think, who has been over the ground can doubt that 

 floating ice has been the instrument of their formation. It is, of 

 course, difficult for one who has not had the opportunity of 

 examining the glacial deposits of the Northern Hemisphere to 

 speak positively on such a subject ; but the whole of the 

 j^henomena displayed so exactly agree with what the text-books 

 tell us of the appearance of glacial beds that one must side with 

 Daintree, Selwyn, and Dunn in the matter. 



