176 PEDINA. 



" 4th. The Pedina aspera, Agassiz, which is distinguished from the preceding species by 

 its more granular aspect, by its principal tubercles being larger and more prominent, by its 

 more numerous secondary tubercles, and by its poriferous zones being still more narrow 

 than those of Pedina Gervillii." 



M. Cotteau adds, that stratigraphical geology completely justifies these distinctions ; 

 Pedina rotata comes from the Inferior Oolite of England, Pedina Gervillii is met with 

 in the Callovien stage of the Sarthe, Pedina suUevis characterises the inferior layers of 

 the Coral Rag, and Pedina aspera appears to be special to the Kimmeridge Clay. 



Locality/ and Stratigraphical position. — This species was first found in the upper 

 ragstones of the Inferior Oolite, in a thin marly vein, which, in some places, rests on 

 the Trigonia grit, in the same bed with Ammonites ParJcinsoni, Sow. I have collected 

 it from this stratum at Shurdington, Cold Comfort, and Hampen, in Gloucestershire ; 

 in the latter locality it is associated with Holectypus depressus, Leske, Holectypus 

 hemisphcericus, Desor, Echinohrissus Hugi, Agass., EcJiinobrissus clunicularis, Llhwyd, 

 Clypeus sinuatus, Leske, and Stomechinus intermedins, Agass. The Rev. A. W. Griesbach 

 has discovered two fine large specimens in the Cornbrash of Rushden, Northamptonshire. 

 Professor M'Coy gives the Great Oolite of Minchinhampton as the locality for the 

 specimen in the Cambridge Museum. The specimen, figured in the 'Memoirs of the 

 Geological Survey' was found in the upper beds of the Inferior Oolite, at Hampen, 

 in the same bed from whence the specimens figured in PI. XIII were obtained. 



Pedina Smithii, Forbes. PI. XIII, fig. 2 a, b, c. 



CiDABis, sp. 2 of William Smith's Stratigraphical System of Organized Fossils, p. 109. 

 EcHiNOPSis Smithii. Forbes, Memoirs of the Geological Survey, Decade V, pi. 3. 



Notes on British Echinopsis. 

 — — Morris, Catalogue of British Fossils, 2d edit., p. 78. 



Test pentagonal, much depressed ; ambulacral areas narrow, and extremely prominent, 

 with two rows of tubercles, which closely alternate in the lower half of the area, but 

 abruptly cease on the upper half ; inter- ambulacral areas wide, with two rows of primary 

 tubercles, which occupy the zonal sides of the plate, and form a continuous series 

 from the mouth to the disc, and two short secondary rows, which extend from the 

 peristome to the circumference, where they abruptly cease ; the miliary zone is wide, 

 and covered with numerous granules, among these several small perforated tubercles occur ; 

 mouth opening large, peristome with deep incisions, and unequal-sized lobes. 



Dimensions. — Height, about one inch ; transverse diameter, nearly two inches. 



