182 



Mammaliferous Drift. 



At several localities, within two and three miles of Croydon, 

 the clayey loams and associated gravels that form the more 

 superficial deposits of this horizon have yielded species of extinct 

 Manmialia — of Diprotodony Palorchestes Azael, FhascoloiJiys, &c. 



At about the position indicated on the Section, carbonaceous 

 debris was obtained, some years ago, at a depth of 50 feet ; on 

 this bare fact, an appeal is made to speculators to invest capital 

 in a search for coal at this place. The comparatively recent 

 geological age of the Mammaliferous Drift had been early proved 

 by me by the discovery of chalky limestone-pebbles, containing 

 the Eocene-species, Turritella Aiding cp, in the loams forming the 

 cliffy banks of the River Torrens near the present Weir, whilst 

 later discoveries of mammalian debris in the same deposit have 

 settled the relative position of this geological horizon. Having 

 in view the age of the deposit, its limited vertical depth, and its 

 restricted area on the east, as made certain by the data derived 

 from the Croy don-bore, there seems to me very little hope of any 

 useful purpose to be served by sinking in it in search of coal, 

 unless it be to supply the exact position of boundary-lines between 

 the successive formations, instead of the conjectural ones of my 

 section. 



The details of the nearly 400 feet of Mammaliferous Drift 

 passed through in the Croydon-bore are appended. The base of 

 the formation has been tixed at the first marine bed, though a 

 higher position may have been selected on lithogical considera- 

 tions ; seeing that the main mass of the Older Pliocene consists 

 of sharp sands and those at 380 feet closely resemble an ^olian 

 formation, it may be questionable if the beds from 350 to 395 

 feet should not be included in the Older Pliocene. 



Older Pliocene. 



The Croy don-section supplies very detailed information as to 

 the thickness and nature of the beds passed through ; the official 

 record I have in part revised, as the outcome of a careful exam- 

 ination of the material submitted to me. In these particulars, 

 the Dry Creek-bore was deficient, though on the other hand the 

 palseontological data furnished by the Croydon-bore are meagre, 

 probably because of the very much less quantity of material 

 available. Nevertheless the small collection of fossils, which has 

 been gathered, proves that the Dry Creek shell-bed was reached 

 in the Croydon-bore at about the same horizon, 340 feet below 

 sea-level. 



Some species additional to those obtained from the Dry Creek- 

 bore occur, but they do not affect the general palasontological 



