OF DENISON UNIVERSITY 



135 



genus Plairodictyum Nicholson's work, Pal. Tabulate Corals should 

 be examined. The Australian fossils here described are part of a 

 series kindly forwarded to us by Mr. John Mitchell of Bowning. 

 They have all been obtained in the district near Bowning, New South 

 Wales, Australia. The fossiliferous rocks here are all referred to the 

 Upper Silurian Group They form a great synclinal basin from east 

 to west. Near the base of the exposed series is a bed of hardened 

 greyish-grown shale about 50 feet thick. This has furnished the 

 tribolites the first two species of Cyathophylliim and the Plcurodichum. 

 Beneath this bed of shale is a layer of limestone containing many 

 corals. From this we obtained Cyathophyllum Boloniense and the 

 Etidophyllum. The tribolites are all characteristic Silurian types. 

 The corals have their nearest analogues in the Devonian formations. 

 We find associated with the tribolites also two species of Pinnatapora 

 or Glanconome, Goldfuss. Species of this genus usually occur in car- 

 boniferous and sub-carboniferous strata, and are not known to descend 

 below the Devonian series elsewhere. It is evident from these 

 remarks that a careful study of the fossils of this district would be an 

 unusually valuable contribution to the study of paleontology. 



CARBONIFEROUS. 



Chainodictvum laxum, Foerste. 



Siuce the first publication of this species we have obtained good 

 casts of the porifous face. This shows that the cell orifices are elon- 

 gated and are arranged in oblique rows across the branches ; their 

 partition walls appear at the surface as more or less wavy, usually in 

 osculating striae. Two or three cells occupy the width of a branch. 



McCoy in Carb. Foss. Ireland, i)ul)lishecl Retepora iindata with 

 the following description : "Irregularly cup-shaped, interstices anas- 

 tomosing, flattened ; fenestrule ovate, pointed at one end ; poriferous 

 face with five or six rows of pores in cpiincnnx ; reverse with waved 

 or scale like, semicircular ridges. This sj)ecies we have seen from 

 Kildare and identify with our genus, 'i'he lunate crossstriations on 

 the reverse side are also consjjicuous. The cell apertures are sim- 

 ilarly elongated and bordered by raised ridges. Compared with our 

 species however the branches are much coarser and broader ; being 



