Speight. — The Tertiary Beds of the Trelissick Basin. 



345 



centage being 19 — exactly the same figure as Thomson arrived at from a 

 restricted list. This clearly indicated a Lower Tertiary age. It is note- 

 worthy, also, that this bed, one of the lowest in the series, does certainly 

 contain the lowest percentage of Recent forms yielded by beds which are 

 admittedly of Tertiary age. 



The next higher fossiliferous horizon in the tuft's is that underneath k the 

 lower layer of limestone, the special localities being (1) above the upper 

 limestone gorge of the Porter, and (2) the gorge of the Broken Eiver below 

 the road-crossing. 



In the former the following were collected by Thomson : — 



*Callistoma aucklandicum Smith. 

 *Calyptraea maculata (Q. & G.). 

 *Cantharidus tenebrosus A. Ad. 

 *Emarginula ivannonnensis Harris. 

 *Natica australis (Hutt.). 



*Natica zelandica Q. & G. 



Pecten hutchinsoni Hutt. 



Pecten yahlensis T. -Woods. 

 *Siphonium planatum Sut. 



Of these, all but two species are Recent. In addition to the above 

 McKay collected from this locality in the greensands a species of Tellina 

 and also Ostrea subdentata (Hutt.), although on the authority of Hutton this 

 specimen really came from the marls. In any case, this Tertiary species 

 comes from beds underlying the tufts conformably, according to all authori- 

 ties, and serves to emphasize further the Tertiary age of the beds in this 

 locality at this particular horizon. 



In the tuft bed below the limestone in Broken River the following were 

 collected, principally by Thomson :— 



Ampullina suturalis (Hutt.). 



Ancilla papillata (Tate). 

 *Callistoma aucMandicum Smith. 

 *Calyptraea maculata (Q. & G.) 



Cardium spatiosum Hutt. 



Clio tatei Sut. 



Crassatellites cordiformis Sut. 

 *Crepidirta crepidula (L.). 



Cypraea ovulatella Tate. 

 *Diplodonta zelandica (Gray). 

 * Emarginula wannonnensis Harris. 



Flabellum laticostatum T. -Woods. 

 *Fulgoraria gracilis (Swains.). 



Lima huttoni Sut. 



Modiolaria elongata (Hutt.). 

 *Natica zelandica Q. & G. 



Panopea orbita Hutt. 



Pecten williamsoni Zitt. 



Pholadidea concent rica Sut. 



Phos cingidatus (Hutt.). 

 *Psamniobia lineolata Gray. 

 *Siphonalia mandarina (Duclos). 

 *Siphoniu7n planatum Sut. 

 * Tellina eugonia Sut. 



Troclms nodosus Hutt. 



Of these, eleven are Recent species, five of the seven from the upper 

 gorge of the Porter being identical. 



From this tuff bed McKay also records (loc. cit., p. 7-1) numerous speci- 

 mens of brachiopods of the genera Terebratula, Waldheimia, Terebratella, and 

 Rhynchonella. McKay also records the occurrence of spines and plates of 

 Cidaris, and specimens of Echinus enysi Hutt., as well as Turbinolia and 

 various other corals. 



The upper tuff bed at the junction of the Thomas River and the Porter 

 is perhaps the most prolific locality in the whole district. The following 

 is the list of fossils collected from there, the name of the collector being 



