﻿100 



SUPPLEMENT TO THE BRITISH 



ironstone, or zone of Am. Bucklandi, at Eston mines, in Yorkshire. I record the presence 

 of this fossil merely in the hope that better examples may be sought for, and its provi- 

 sional identification made certain. 



40. Spiriferixa oxygona, E. Desl. Sup., PI. XI, figs. 1 to 5. 



Spiriferina oxygona, E. Desl. Bull. Soc. Linn, de Normandie, vol. iii, pi. iii, figs. 



4—10, 1859. 



— — R. Tate. Geol. Mag., vol. vi, p. 552, December, 1869. 



Sp. Char. Shell wider than long. Dorsal valve transversely semicircular ; ventral 

 valve much deeper than the opposite one, beak large, entirely straight, and at right 

 angles to the plane of the dorsal valve, or slightly incurved at its extremity. Hinge-line 

 straight ; slightly shorter than the greatest width of the shell ; area of ventral valve large, 

 flat, and triangular, fissure moderately wide. Surface of valves ornamented with from 

 fourteen to twenty or more angular ribs, divided in the ventral valve by a prominent 

 angular mesial fold, and in the dorsal valve by a wide deepish angular sinus. Numerous 

 small spinules cover the surface of both valves. Proportions very variable ; a large 

 example measured 14 lines in length by 22 in width and 13 in depth. 



05s. Mr. Deslongchamps does not appear to have published a complete description 

 of his species, but states that it is easily distinguishable from other Liassic forms by the 

 beak of its ventral valve being completely straight, by its angular ribs, and, lastly, by its 

 general angularity ; hence the name oxygona. Mr. Deslongchamps' short description is 

 accompanied by eight excellent figures, which agree in every particular with the speci- 

 mens found in England. In some of the French examples as many as thirty-two libs 

 may be counted on each valve, and the spines cover in a regular manner every part of the 

 shell with the exception of the area. 



Mr. C. Moore appears to have been the first British palaeontologist who noticed the 

 presence of this fossil in England ; he mentions having found it in the Middle Lias of 

 Whatley. Some very large and fine examples were subsequently discovered by Mr. 

 Beesley in the Marlstone, or near the middle of the Ammonites sjrinafus zone, at King's 

 Sutton, in Northamptonshire, at about four miles south of Banbury. The fossil is 

 stated to be tolerably plentiful at the spot. For a full account of the formation and 

 locality of King's Sutton, see Mr. Beesley's paper in the ' Proceedings of the Warwick- 

 shire Naturalists' and Archaeologists' Field Club ' for 1872. Mr. Beesley informs me 

 likewise that some specimens have been got at Adderbury, just opposite King's Sutton, 

 on the Oxfordshire side of the river Cherwell, and at Byfield in Northamptonshire. In 

 France the species was discovered by Mr. E. Deslongchamps in the Middle Lias of 

 Fontaine-Etoupe-Four and May in Normandy. 



