﻿9G MR. S. S. BUCKMAN ON CERTAIN JURASSIC [Feb. I9IO r 



Remark s. — This species is interesting, as being about one of 

 the earliest of the Oppelids to develop periphero-lateral tubercles : 

 there are apparently successive independent developments of such 

 'spinigerous' forms as (Ecotraustes, Oppelia, Hecticoceras, Bonarellia, 

 and Taramelliceras. The actual earliest form is probably Oppelia 

 ( (Ekotraustes) sp. nov. indet., figured by Yacek from the Oolite of 

 Cap San Vigilio. 1 That Oolite is evidently, judging from the 

 Ammonites, of varied dates, extending from aalensis to discites ; 

 the latter, probably, is the date of Yacek 's unnamed form. 



Locality, etc. — Frogden Quarry, Oborne (Dorset), in the 

 Marl Bed with green grains ; Dundry (Somerset), in the Ironshot 

 Oolite. Its date is therefore sauzei hemera (Bajocian). It is rare. 

 It might be expected in the lied Beds of Chideock Quarry Hill ; 

 and perhaps at Burton. 



Family Hildoceratidae. 

 Genus Darellia, S. Buckman. 



For description of the genus and species, see ' Monogr. Inf. Ool. 

 Amm,' (Paloeont. Soc.) Suppl. 1904, p. cxii. 



Darellia alta, sp. nov. (PI. XI, figs. 2 & 3.) 



Description. — One of the carinatitabulate Hildoceratids, 

 much compressed, with a small narrow-stepped umbilicus, and 

 ornament passing from obscuricostate to levigate. 



Distinctio n. — From Darellia polita, the smaller umbilicus, 

 the narrower periphery, and the more elevated carina. 



Remarks. — This is one of the rare and interesting Cotteswold 

 species which serve to show that the Lower Trigonia Grit of the 

 Cotteswolds is contemporaneous with certain strata in Dorset. 



Localities and strat a. — Frith Quarry, near Pains wick, 

 Gloucestershire (Cotteswolds), Lower Trigonia Grit ; Dundry 

 (Somerset), Limestone and Marl Beds ; Stoke Knap (Dorset), in the 

 Building-Stone : all these would be strata of the zone of discites, 

 Mr. Charles Upton possesses a specimen from Rodborough, Glouces- 

 tershire (Cotteswolds), presumably from Lower Trigonia Grit, which 

 is abnormal on one side, apparently a reversion, due to injury, to 

 the style of Darellia semicostata. 



Genus CEdania, S. Buckman. 



For description of the genus and species, see ' Monogr. Inf. OoL 

 Amm.' (Palceont. Soc.) Suppl. 1904, p. cvii. 



U^dania obscura, sp. nov. (PI. IX, figs. 4 & 5.) 



Description. — This is one of the carinatitabulate Hildo- 

 ceratids ; but the keel is small. It is a thin form, though the body- 

 chamber shows a tendency to thicken • the umbilicus is small, step- 

 form ; the ornament consists only of obscure falcate ribs. 



1 Abhandl. k.k. Geol. Eeichsanst. vol. xii (1886) pi. ix, fig. 13. 



