166 Notices of Memoirs — Geology of Kimberley, W. Australia. 



in which Mr. Arthur Nicols, speaking from recollection, says that 

 " Teredo navalis is certainly able to endure a long continuance of 

 freshwater. At Brisbane the river is subject to freshes, one of 

 which lasted ten days, when the flood was so powerful that ocean 

 steamers could not get up. Salt-water is said at floods to ascend 

 thirty miles beyond the town, which is itself twenty-five miles from 

 the Pacific, — but the ebbs are more fresh than salt. Piles have to 

 be protected with Muntz metal." 



It will be seen that more definite information is required on all 

 the points raised. There is said to be a freshwater Carcharias in 

 the rivers of Fiji, and it would be interesting to learn whether it 

 also ever lives wholly beyond the tidal reaches, or merely ascends 

 rivers, as seals will, in search of food. 



It thus appears, so far as we can go at present, that Teredo 

 chiefly flourished during our Eocene time in waters that were clearly 

 estuarine. The purely salt water reaches of the great river, such as 

 those in which the London Clay and Bracklesham beds were 

 deposited, were less favourable to its development than the almost 

 fresh-water reaches in which the Bournemouth fresh-water beds and 

 the Lower Bagshot of the London Basin were formed. In this last 

 class of deposits there is no other sign whatever of aquatic life, either 

 fresh or salt, and we are forced to conjecture that perhaps frequent 

 change from quite fresh to quite salt water was the excluding 

 cause. In what were perhaps more littoral marine beds, out of the 

 influence of the river, such as those of Heme Bay and Highcliff, the 

 Teredo seemed comparatively to languish, and it is quite excluded 

 from the higher reaches of the river in which the Lower Bagshots 

 of Studland and Corfe were formed, and which from the presence of 

 Unto would appear to have been wholly freshwater. It had no place 

 in the lacustrine deposits of Headon and Bembridge, and even the 

 brackish and salt waters of these formations seem to have been quite 

 unfavourable to it, being, it appears, from their teeming life, too 

 permanently either fresh or salt. Without its presence we might 

 never have suspected that many important masses of sediment 

 containing terrestrial vegetation had ever been formed within the 

 influence of the tides of the sea. Sufficient has been said to 

 illustrate the peculiar local significance that the record of this 

 destructive mollusc may possess with regard to the origin of a 

 formation. It is noteworthy that the Eocenes possess three distinct 

 types of Teredo which have not as yet been distinguished. 



UOTICES OP HVCIEIMIOI^S- 



I. — Report on the Geology of the Kimberley District, 

 Western Australia. By Edward T. Hardman, etc., of H. M. 

 Geological Survey of Ireland. Fcap. pp. 22, 16 Plates, Map. 

 (Perth, W.A., 1884.) 



THE country described in this very excellent report comprises that 

 portion of Western Australia extending from Eoebuck Bay 



