178 



the Palaearctic fauna, though well represented in the Parisian 

 Eocene. It is remarkable that it is here represented by a species 

 so closely near to L. jmllidula as to cause hesitation to inscribe 

 it under a different denomination. One is almost tempted to 

 place it in the same category as Saxicava arctica, Lasaea rubra, 

 and a few others which are common to the temperate seas of both 

 hemispheres. Cyammm is Palfeo- and Neo-arctic, though known 

 by one species in the Paris-Basin. 



A fact of some significance, suggestive of a colder climate pre- 

 vailing during this life-epoch, as comj)ared with the Miocene on 

 the one hand and the Recent Period on the other, over the same 

 areas, is the large proportion of diminutive shells, either in re- 

 gard to the genera to which the species belong, or in re- 

 gard to identical species of older or recent date. This is very 

 conspicuous in the genera Columhella, Phasianella, and Chione, 

 and exemplified by the species Corhula epka??iilla,Arca navicularis, 

 Hemimacti'a Howchiniana, Cacullcea Corioensis, Ancillaria 

 pseudaustralis, Pelicaria coronata, ifec, whilst on the other hand 

 Saxicava arctica attains to large dimensions, as in forma 

 Angasi. 



The fauna is certainly distinct from the Older Miocene, as 

 known at the localities previously named, and is a new one for 

 Australia. In its higher percentage of living species it occupies 

 an intermediate place in the scheme of geological periods between 

 the Miocene and the Recent ; and though I provisionally employ 

 the stratigraphical designation of Older Pliocene for it, I am 

 fully aware that the proportion of living species is too low^ to 

 justify its employment as measured by the European standard ; 

 yet in this case the percentage-principle of classification does not 

 adequately express the modern complexus of the whole fauna. 



The majority of the living species range from low-water mark 

 to five or six fathoms in depth. Most certainly the fauna belongs 

 to the shallow water. The sharp sands and the fragmentary and 

 unrolled condition of the fossils are rather suggestive of shallow- 

 water material having been swept into a depression of the sea 

 bed, or perhaps indicative of rapid accumulation on a sinking 

 bottom. 



The general elevation of the fossiliferous Miocene skirting the 

 east coast of Gulf St. Vincent is about 80 feet above sea level ; 

 so that there is a difference of level of about 500 feet between the 

 marine equivalents of the Miocene and Older Pliocene. The 

 Older Pliocene fossil-bed is at from 320 to 410 feet in the Dry 

 Creek bore, which is equal to 306 to 396 feet below sea level, and 

 if we deduct 36 feet as the probable depth at which the species 

 lived, then there has been a general depression of the coast-line 



