150 ON" SOME TEETIAET ArSTEALIAJ^ POLTZOA. 



PTJSTrLIPOSA TJlS'GrLATA, U.S. 



Polyzoary cylindrical, dicbotomoiisly branclied; cells very 

 slightly projecting and disposed in circles at equal distances, 

 longitudinal lines of cells of different circles spiral ; transrerse 

 section sliows six partitions rayed liked tlie spokes of a wlieesl. 

 Common ; Mount G-ambier. 



TtJEULIPOIIA GtAMEIEEEXSIS, U.S. 



Polyzoary erect, adhering by a slender cylindrical root ; cells 

 dispersed on one side, but a few tubes sometimes opening beliind 

 near tlie margin ; tubes simple, sliglitly recurved, long and 

 crowded, distinctly traceable behind but faintly so in front ; 

 moutli simple, disposed in irregular spiral lines in front ; when 

 worn the mouths are very plain in lines almost encircling the 

 cylindrical axis. Mount G-ambier"; not common. 



PrSTrLIPOEA COEErGATA, U.S. 



Polyzoary cylindrical, branched or lobed in the thicker speci- 

 mens ; cells tubular, recurved, a very prominent irregularity 

 disposed all round, and distant space bet^^een the cells corru- 

 gated or wrinkled. In what seems to be the older branches of 

 this fossil the cells are much closer and more numerous, the 

 corrugations on the interspace cannot be traced and the branches 

 are terminated by congeries of sessile cells. Mount G-ambier, 

 limestone ; very common. 



Conclusion. — The publication of these fossils may serve to 

 identify the beds in other localities. The zone itself, whether met 

 at Mount Gambler, jN'arracoorte, Cape Otway, Portland, or Table 

 Cape, Tasmania, is pretty constant in character, being one 

 immense mass of f oraminifera, polyzoa, with few broken shells,, 

 echini, teeth, &c., all showing a very deep sea deposit. It 

 indicates probably the lowest depths of subsidence in our tertiary 

 seas — and a depth of over 300 fathoms. 



[Plates.] 



