84 



found several feet in thickness at the base of the inner sandhills 

 bordering the coast, where there is at present no evidence what- 

 ever of lagoon area. 



Professor Tate, in his Geological Notes on Kangaroo Island, 

 already referred to, says, " In most instances the margin of the 

 inundated ground is fringed by a sheet of calcareous travertine of 

 several inches thick, derived from, and including Buliiuis. Not 

 always is the mollusk living over the same area, inasmuch as 

 through lapse of time the waters have acquired a too saline 

 property for its existence. The large sheet of water called 

 Murray's Lagoon is in this state ; whilst its former extension 

 and comparative freshness of its water are indicated by the con- 

 siderable area above present water level covered by a white 

 chalky clay teeming with the shells of a species of that freshwater 

 water-snail." The diagnosis of Professor Tate in this particular 

 seems to be at fault, as the remains referred to Bulinus are 

 really those of the common brackish water species Coxiella 

 conjusa^ found abundantly in our marine marshes and saline 

 lagoons. In this determination I am supported by Dr. Verco 

 and Mr. Bednall. 



The country lying between the watershed and the coast 

 possesses few features of geological interest. A superficial 

 travertine crust, with patches of sand, eiFectually hides the 

 underlying rocks, the difficulties of travel being very great by 

 reason of a dense scrub, which for the most part is impenetrable. 

 In company with a guide I made for the coast at the Brecknell 

 Sandhills, about nine miles from Hawk's Nest, in a south-west 

 direction, taking advantage of the old whalers track to the beach 

 so far as it could be recognised. The limestone passes under the 

 blown sand bordering the coast, and forms high cliifs on the 

 shore. 



The hills of blown sand, which everywhere border the coast,, 

 are remarkable for their great extent and height. In the 

 peninsula headed by Cape Gautheaume they have a breadth of 

 nine miles, and at the Brecknell from one to one-and-a-half miles. 

 Over much of this area the sand is constantly shifting, and pro- 

 duces hills of remarkable size and aspect At the Brecknells one 

 hill was probably not less than 300 feet high, destitute of a 

 single blade of green, a mountain of clean white sand like driven 

 snow. The struggle between living vegetation and wind, in 

 this disputed ( ountry, is severe and never ceases, and often leads 

 to curious effects. Tree capped heights are separated from a 

 range and entirely surrounded with deep-cut wind drifts, which 

 are surely undermining the last vestige of vegetation on its 

 island height. Or, in other instances, chemical action has so far 

 consolidated a small patch of sand that it is able to defy the 



