29 



INOTES ON THE GEOLOGY OF THE CRADLE 

 MOUNTAIN DISTRICT, 



With a Bibliography of the Pleistocene Glaciation of 



Tasmania. 



By W. N. Benson, D.Sc, B.A., F.G.S. 



Plates I.-IV. 



(Communicated by W. F. D. Butler, M.Sc, LL.B., B.A.) 



.(Read Brd April, 1916. Issued st-parately 28tli July, 1916.) 



Owing to the kind invitation of Mr. Rodway and 

 Professor Flynn, the writer had the good fortune to be 

 a member of a party spending the last week of 1915 in 

 Mr. Weindorfer's Accommodation Hut near Cradle Moun- 

 tain in the north-west of the Tasmanian highlands. 

 'Though there was little opportunity for detailed geolo- 

 gical work, many interesting features were observed, 

 which, at the request of the leaders of the- party, are 

 bere recorded, and correlated with the scattered references 

 to this region in the writings of the few geologists that 

 have previously been in the neighbourhood. A sketch 

 map of the geological features, and a topographical sketch 

 maiD are also given, based on a manuscript map by Franz 

 Malscher, supplied by Mr. Weindorfer, and amended in 

 accordance with surveys made by the present party. The 

 following account must be considered rather tentative, 

 since lack of time prevented complete verification. 



Cradle Mountain may be reached most easily by the 

 road from Sheffield through Wilmot and the Middlesex 

 Plains, a distance of forty miles. The track crosses the 

 Isis' River and Pencil Pine Creek, and then follows the 

 X)ove River to the foot of the mountain. The forma^ 

 tions traversed by this route, or adjacent thereto, are 

 the Pre-cambrian schists, the Cambrian sandstones, quartz- 

 ites and conglomerates, Silurian limestones, Devonian 

 -granite, and Tertiary basaltic rocks (which are of several 

 types, varying from dolerite to tachylite), and alluvial 

 deposits. (1). 



The four main formations in the vicinity of Cradle 

 Mountain and Barn Bluff are the Pre-cambrian schists 

 and quartzites, the Permo-carboniferous conglomerates, 

 •F8iiidstones and mudstones, the Cretaceous dolerite, and 



(1) W. H. Twelvetrees. Bibliography No. 42, 



