184 



TERTIARY ROCKS OF AUSTRALASIA, 



Professor Marsh, who has recently devoted much atten- 

 tion to these earher forms of the Mammaha, has latterly^ 

 given good reason for the view that it is extremely 

 doubtful whether these earlier forms can jjroperly he 

 referred to the order Marsuj^ialia. Many of them appear 

 to depart from the jiormal type of Marsupial structure, 

 ap]5roximating to the Insectivora ; and for these and 

 other reasons. Professor Marsh has come to the conclu- 

 sion that it is more probable that they represent two 

 distinct primordial groups, termed by him Pantotheria and 

 Allotheria, both of which are supposed to have no living 

 representatives. 



Local General Features. 



Taken as a whole, the general features of the Tertiary 

 system in Tasmania correspond exactly with those of the 

 mainland of Austraha. The rock formations may be con- 

 veniently divided into four main groups, in descending- 

 order, as follows : — 



( Older raised terrace drifts, often over- 



JNeogene. 



1 



ri. 



Palaeogene . . { 



lying the plateaux of basalt. 



Basaltic sheets and associated tuffs 

 overspreading lacustrine forma- 

 tions. 



Lacustrine deposits of great thick- 

 ness and extent, composed of 

 sands, clays, hgnites, travertines, 

 and sometimes including auri- 

 ferous and stanniferous drifts. 

 Contains the remains of a rich 

 and varied flora. 



Marine deposits in the northern 

 part of Tasmania. 



Palaeogene Epoch. 



Marine Formations.— The marine formations occur 

 in isolated patches fringing the northern coast of Tasmania 

 and the islands in Bass's Strait, notably near Cape Grim, 

 Sandy Cove, Table Cape, and Heathy Valley, FHnders' 

 Island. The members present a somewhat uniform 



a Geol. Mag., July, 1887, pp. 297-298. 



