when the water evaporates, this, of course, counteracts the 

 action of the wind, and conserves the fluviatile material of the 

 lake bed ; but it is difficult to imagine how these shallow 

 depressions can be scooped out of sedimentary deposits ex- 

 cept by the wind, and as there seems to be evidence that the 

 banks show a tendency to sheer in the windward direction, 

 it lends plausibility to the assumption. 



Fauna of the Lagoons. 



The existence of foraminiferal shells in the silt of the 

 Yorketown Lagoon was brought under my notice by Mr. 

 Matthews, of Yorketown. I was unable to visit the lagoon 

 in question, but Mr. Matthews kindly placed some of the 

 material in my hand for examination. I found a consider- 

 able number of dead shells of Polystomella striato-punctata, 

 and P. maceUa. These forms are characteristically 

 estuarine in habitat, and the individuals found in the lagoon 

 were small, starved varieties of the species, giving evidence 

 that their lot has been one of struggle for existence under 

 adverse conditions. With the foraminiferal remains there 

 also occur a few ostracoda and the gastropod, Coxiella 

 confusa. The last-named may be regarded as ubiqui- 

 tous in its distribution over the marginal maritime 

 belt of Southern Australia, under brackish water conditions, 

 as well as in many of the isolated lagoons in inland positions. 

 No organic remains (so far as I know) occur in the circular 

 lagoons that would indicate a distinctively marine fauna, and 

 the presence of foraminifera in the Yorketown lagoon may 

 probably be explained as a sporadic colony, introduced at 

 some period by sea birds carrying foraminiferal spawn on 

 their legs, the introduced forms maintaining a precarious 

 existence until either the increasing salinity of the water, 

 or the temporary drying up of the lagoon, led to the extinction 

 of the colony. 



Analogous Features in Kangaroo Island. 

 It may be regarded as a corroboration of the theory advo- 

 cated in this paper that in Kangaroo Island several lagoons of 

 the same type as those on the Peninsula occur in the north- 

 east portion of the island, and under similar geological con- 

 ditions. There are the same outliers of Eocene limestona 

 separated by areas from which the limestone has disappeared. 

 The glacial clay underlies the Tertiary limestones, and forms 

 the retentive floors for the drainage. The lagoons also are ?x- 

 cavated in this clay with exposure of erratics on their flanks, 

 as has been described in the case of Yorke Peninsula. 



