322 DR. A. M. DAVIES AND MR. .T. PR1XGLE ON [June I9I3, 



From fossiliferous limestone, 354 feet (striatum zone) : — 



*Cardinia. attenuata (Stutchbury). I *Androgynoceras cf. intracapricornvs 



* Ostrea sp. (Quenstedt) — allied to A. hybrida 

 *Pecten diseiformis Schiibler. but less evolute, ornament not 

 *Pseudopccten oeqitivalvis (J. coarse enough for the cheltmse 



Sowerby). series. 



~*Plagiostoma sp. I *A. aff. latcecosta (J. de C. Sowerby). 



At 431-432 feet (valdani or Jameson i zone) : — 



■|" Orbiculoidea aff. holdeni (Tate). Ammonites, immature and un- 



identifiable. 



From fossiliferous limestone, 438-440 feet 6 inches (Jamesoni zone) : — 



* Rhynchonella cf. curviccps (Quen- 1 *Pecten diseiformis Schiibler. 



stedt). ' *Pseudopeeten eequivalvis (J. 



t Rhynchonella rimosa von "Buch. Sowerby). 



'*'[ Rhynchonella rimosa-multiplicata *PlagiostomacLgigantca J. Sowerby. 



(Quenstedt). Fragments of other lamelli- 



\ Rhynchonella variabilis (as figured branchs. 



by Davidson). fBiseohelLv aratits (Tate). 



* Terebratula radslockensis Davidson. + Trochus sp. 



**t Zeilleria waterhousei (Davidson). t Echioceras microdiscus (Quenstedt), 



~*fZeilleria ait '.waterhousei (Davidson). derived. 



tSpiriferina aff. punctata (J. Buck- fBelemnites sp. 



man). tEeptilian bone, fragments. 



(6) Palaeozoic Eocks. — (i) Tremadoc Shales. 

 [J. P. & A. M. D.] 



Unfortunately, when the boring entered the Palaeozoic rocks 

 it was found that the soft dark clay of the Lower Lias and the 

 greenish-grey shales of the Tremadoc had got mixed. By carefully 

 cutting the core, however, one of us secured a small specimen which 

 clearly shows the relationship between the two formations ; but, 

 apart from this evidence, the dips obtained at a short distance 

 below the junction strikingly demonstrate the existence of a marked 

 unconformity, and prove beyond any doubt that the low-dipping 

 Jurassic clay rests on the upturned edges of highly -inclined 

 Tremadoc Shales. No pebbles were found in the basement-bed; 

 but, as has already been noted (p. 311), the limestone overlying the 

 clay contains fragments of the older rocks, so that the erosion of 

 the Palaeozoic floor outside the Calvert area must have continued 

 for some time during the deposition of the lowest beds of the 

 Lias. 



The highest beds of the Tremadoc between the depths of 443 

 feet 6 inches and 496 feet present a wholly different appearance when 

 compared with the lower beds ; and, when the core was brought to 

 the surface, it was thought that Coal Measures had been encountered, 

 until the discovery of a graptolite - fragment ( Clonograptus ?) 

 placed the age of the beds beyond doubt. The uppermost 36^ feet 

 are soft, greenish-grey, slightly-micaceous shales. In the core 

 they were distinctly green in hue ; but, on drying, the colour 

 has become greenish grey. On several horizons, particularly near 



