POSITIONS OP THE TRIGONI^ OP NORTH OXFORDSHIRE, ETC. 37 



same county. The interest of the discovery is further enhanced by 

 the recognition of the exact horizon of the fossil, at nearly the top 

 of the Upper Lias and below Mr. Sharp's stage E of the Northampton 

 Sand. Mr. Thompson's notes on its position agree with my own. 

 He writes, " The shelly band, a few inches in thickness, is about two 

 feet below the junction (with the Inferior Oolite) where now work- 

 ing ; but the men say it dips so rapidly on each side of its present 

 position that they had met with it in the same pit thirteen feet 

 below the junction." The associated fossils are Ammonites hifrons, 

 Brug., Gresslya donaciformis, Phil., Inoceramus duhius, Sow., Pro^ 

 tocardium substriatulum, d'Orb., Cucullcea, sp., &c. 



Teigonia pulchella, Ag. — This also, an Upper Lias form, has 

 been recorded from the neighbourhood of l^orthampton, though only 

 as a Drift fossil*. Probably ere long we may hope to have a record 

 of the discovery of the species in situ, as a layer containing small uni- 

 valves {Ceritliium, &c.), similar to those found by Mr. W. D. Carr, 

 in the Upper Lias of Lincoln t associated with T. i^'^dcheTla, has 

 already been noted by Messrs. Thompson and Crick. The Lincoln- 

 shire horizon of T. pidchella appears to be much lower than that of 

 T. northamptonensis, the former being at the base of the Leda-ovum 

 beds, the latter towards the top. 



Lneeeior Oolite Species. 



The Trigoniae of the Northampton Sand have been catalogued by 

 Mr. R, Etheridge, F.E.S.J, and by Mr. Sharp, E.G.S. § It should, 

 however, be borne in mind that the Inferior Oolite of Oxfordshire 

 neither satisfactorily agrees with the " Northampton Sand " on the 

 one hand, nor allows of easy correlation with the Cotteswold type 

 on the other. Inasmuch as the latter series has presented many 

 points of relationship, I have attempted a comparison ||, and have 

 summarized the matter in the following table, here slightly 

 altered : — 



* "On the Drift deposits of Wymington," by W. D. Crick (Northampton 

 Nat. Hist. Soc. Proceed. 1883). 



t " On the Lincoln Lias," by W. D. Carr (Geol. Mag. April 1883). 



X Appendix to Prof. Judd's Gaol. Rutland, by E. Etheridge, F.R.S. (Mem. 

 Geol. Surv. 1875). 



§ "Oolites of Northamptonshire," by S. Sharp, F.G.S. (Quart. Journ. Geol. 

 iSoc. vol. xxvi. p. 388). 



!| " On the Eelation of the so-caUed ' Northampton Sand * of North Oxford- 

 shire to the Clypeus-grit," by Edwin A Walford, F.G.S. (Quart. Journ. Geol. 

 Soc. vol. xxxix. p. 224). 



