Tertiary Limestone— Of this only one small outcrop was 

 met with, but from its thickness it is probable that there 

 is a good deal hidden under the loose sand drift in the south 

 of the island. It occurs on the bank of a creek which runs 

 into the Seal River, at a spot about one mile due east of 

 the south-east corner of E. Mason's Block, but the outcrop 

 is so small that it is very easily overlooked. A thickness 

 of about twenty feet only is visible, dipping slightly to the 

 west, and the length of the outcrop is only about forty feet, 

 the rest being hidden under sand and detritus. The upper 

 strata are of fine broken shell sand, very hard and firmly 

 cemented, the lower of coarse fragmental material with 

 complete shells and pebbles of schists and quartzites, from 

 which we may infer that the area was undergoing subsid- 

 ence, the coarser material with complete shells representing 

 the deposit close inshore, the finer material that when it 

 was farther out. Mr. W. S. Dun has very kindly examined 

 the specimens collected by me, and I quote his notes on 

 them in full :— 



"Mr. Hedley has also seen the specimens and has com- 

 pared the Mollusca with species of the recent marine fauna 

 of the Bassian subregion and the following conclusions have 

 been arrived at. Several well marked forms occur, more 

 especially a Pec ten and a Lima. 



"1. Pectcn.— The Pecten is apparently very closely related 

 to P. antiaustralis, Tate, which would fall in the group 

 typified by the recent P. asperrimua— in fact it is very 

 close iiideid to souk- deep water types of that sp.-eies which 

 were dredged by Messrs. Hedley and May. P. antiaustralis 

 has been collected at Muddy Creek, Aiding* (Miocene V) 

 and from the Dry Creek and Croydon Bores of South Aus- 

 tralia, considered by Tate as Pliocene. P. asperrimus has 

 also been found in the Croydon Bore. 



"2. Lima.— A Lima cf. Bassi, T.-Woods, also occurs. The 

 distribution of this species covers a great geological range. 



