LECKENBY — NOTE ON THE SPEETON CLAY OP YORKSHIRE. 



11 



17. Blue clay with Ammouites and Belemiiites as uuder : — 



Anmnonites rotula. 



venustus. 



concinnus. 



(variety 



with coarser radii). 

 Belemnites jaculum. 



(a short thick species). 



Thickness 12 feet. 



18. A band of clay without fossils except traces of decomposed 

 Hamites 8 feet. 



19. The remarkable "Astacus ornatus bed," with innumerable 

 nodules, each containing an Astacus {Astacus (?) ornatus, Ph.). 3 feet. 



20. Strong clay without fossils. 15 feet. 



21. Another thick deposit containing no fossils except the outer 

 whorl of a large undescribed Ammonite 50 feet. 



22. Another thick bed of stratified clay, forming the Cliff; the 

 lowest portion full of crushed imperfect bivalves i^Mya depressa) ; 

 through its centre runs a band of cement-stone, containing a large 

 smooth Ammonite, and fragments of Hamites maximus ; and imme- 

 diately above the cement-stone-band is a seam of soft stone with 

 Vermicularia Sowerbii 50 feet. 



The cement-stone yields — 



Hamites Banksii (Bean). 

 Ammonites fissicostatus. 



Auricula. 

 Plagiostoma. 



The occurrence of Vermicularia Sowerbii and Ammonites fissicostatus, 

 .which so nearly resembles A. Deshayesi of the Greensand of the Isle of 

 Wight as to be almost inseparable, would seem to refer the upper por- 

 tion of these beds to the ISTeocomian era ; while so characteristic an 

 Ammonite as A. hiplex in the lowest beds would with equal certainty 

 refer the lower ones to the era of the Kimmeridge Clay. Between 

 them w^e have probably the representatives of the Gault in the Hamite- 

 yielding beds, while we are puzzled to account for the presence of 

 such true Oxfordian forms as the coronated Ammonites, A. quadrifidus 

 and A, caveatus, although perhaps these are not more erratic than A. 

 Parhinsoni, which, while it characterizes the Inferior Oolite of the 

 south, occurs in the Grey Limestone at Scarborough, not seventy 

 feet below the Cornbrash. 



