the specimens procured are here tabulated. Very little is 

 known about the mollusca of Australian Devonian rocks, 

 in fact, less than of any other Palaeozoic formation. That 

 an abundance and fair variety must have existed is how- 

 ever incontrovertible. The numerous species of Silurian 

 molluscs described from Yassand Wellington in New South 

 Wales and from Lilydale in Victoria, show that period to 

 have had a rich molluscan fauna : and as the Carboniferous 

 formation has been equally productive, it is inconceivable 

 that the intervening period was barren of this type of life. 

 However the fossils here listed, in spite of their bad preser- 

 vation, will serve to show that such a variety did exist. 

 And this fact in itself supplies another reason for their 

 rarity as fossils. The conditions during Devonian times 

 were evidently very unfavorable to their preservation. 

 The abundance of sandstones and quartzites seems to point 

 to the predominance of shallow water conditions over large 

 areas, a state which would be more favorable to the exist- 

 ence of a brachiopod than a molluscan fauna. The practical 

 extinction of the brachiopods has, in later ages, led to the 

 development of a littoral series of molluscs; but in Palaeo- 

 zoic times it is evident that the predominent type of shallow 

 water shells were the brachiopoda, while the majority of 

 the gasteropods and pelecypods preferred the calmer and 

 deeper waters removed from the shore. There is at least 

 one locality known to the author, where these conditions 

 prevail; and a series of Devonian limestones contain, 

 beside a number of corah. a rich series of molluscs. Brach- 



This locality is near Lake Hathurst railway station, and 

 will be dealt with at a future date. Here it is merely 

 mentioned as some illustration of the distribution of the 

 Devonian fauna. At the present time also, additional 

 localities are continually coming to light, and Devonian 



