46 



OYSTER BED DEPOSIT. 



On the same horizon as the HeUcidce Sandstone we may 

 include the oyster bed dejDOsit of Flinders' Island. This 

 deposit is situated on the banks of the Eiver Arthur, about 

 two miles inland from its mouth. It is about thirty feet 

 above high water level, and a fine exposed section shows that 

 it is composed princij^ally of regular layers of an enormous 

 species of mud oyster, with which is associated Venus aphro- 

 dinoides, and species of Rissoa, Fusns,Alaha, etc., etc., all exist- 

 ing species. Enormous gum trees grow over them. The 

 regular layers of heavy unbroken shells preclude the idea 

 that they have been carried any distance, whether by wind 

 or water. They plainly indicate that the estuary mud or 

 sand in which they lived has been slowlj' elevated into its 

 present position. 



RAISED BEACHES. 



These are found more or less concealed by the overlying^ 

 consolidated sandstones on Badger and Green islands. The 

 shells are all littoral, and are, when found, in consolidated 

 masses. On Badger Ishtud this old beach of shells lies 

 against, and firmly adheres to the metamorphic schists. 



The species are numerous, and seem to be identical with 

 those nov/ existing on the shores of the islands. These 

 beaches are invariably about 40 or 50 feet above present sea 

 level, and sometimes nearly a mile from the present shore 

 line. On the east coast of Badger and Flinders there appears 

 to be intermediate shell accumulations below the recently- 

 formed sand dunes. In them I have frecjuently picked xxp 

 Peduvcidus laticostatus, slightly bleached and worn, together 

 with Cucidlea corioensis; but whether they now exist in the 

 immediate neigh1)ourhood or not I am not yet prcpp^red to 

 say. I never could pick one up on the margin of the sea 

 that was not more or less worn or bleached, and it is possible 

 they ha^ve been washed out of the older sands, upon which 

 the sea may have encroached. It is clear, however, tha.t both 

 P. loticostcdifs and C. corioensis must have existed up to a 

 very recent period on the east side of Flinders' Island. 



There may, however, be a slight difference in the number 

 of radiating ribs. Although I made allowance for the worn 

 edges, there seemed to be fewer ribs upon those foimd by me 

 on the islands named as compared with the fossil species at 

 Table Cape. I am not sure whether the New Zealand exist- 

 ing species have invariably 29 ribs, like our Ta.ble Cape fossil 

 species. It would be interesting to know. The sandhills on 

 the east side of Flinders are protected by the native grass, 

 Sjyinifcx Mrsntus. Their globose spiny heads are perpetually 

 being blown out, wheel-like, to sea. When the long spine 



