Mr. J. F. Walker on Lower- Greensand Fossils. 31 



of the others. Dorsal fia above the middle of the interspace 

 between the root of the ventral and anal, somewhat nearer to the 

 latter. Anal low, scaly, anterior rays imbedded in fat. Caudal 

 short, rounded. The pectoral extends somewhat beyond (in C. 

 scombroides not quite to) the vertical from the origin of the 

 dorsal, its length being one-third of the total without caudal 

 (in C. scombroides rather less than two-sevenths). Ventrals well 

 developed. A small black spot on the root of the lower pectoral 

 rays. The humeral spot and one on the adipose fin are present, 

 as in C. scombroides. 

 Seven inches long. 



VIII. — On the Fossils contained in a Lower Greensand Deposit 

 of Phosphatic Nodules in Bedfordshire. By J. F. Walker, 

 F.C.S., Sid. Suss. College, Cambridge. 



The increasing demand for phosphatic manure has led to the 

 opening, a short time since, of new workings for the extraction 

 of nodules containing earthy phosphates, near Sandy, in Bed- 

 fordshire. A short account of this deposit was communicated 

 by the Rev. P. B. Brodie to the 'Geological Magazine,' and 

 published in that journal for April last. The deposit is referred 

 to the Lower Greensand ; but nearly all the fossils contained in 

 it have been derived from the wreck of preexisting formations. 

 Mr. Brodie mentions an imperfect cast of a species of Rhyn- 

 chonella as the only fossil of animal origin observed by him 

 which appeared to belong to the bed; I have obtained a species 

 of Corbis, nearly allied to Corbis corrugata, Sby. of the Lower 

 Greensand of the southern counties, and have seen a species of 

 Terebratula, both presenting precisely the aspect of Lower 

 Greensand fossils, and exhibiting no traces of having been rolled. 



Of the introduced fossils, the greater part appear to have been 

 derived from the Kimmeridge Clay. Among these are casts of 

 the interior of species of Cardium and of two other bivalves, and 

 of a large Pleurotomar'ia, much worn, — several fragments of the 

 dorsal spines of Asteracanthus ornatissimus and a small portion of 

 a spine of Hybodus, — numerous palatal teeth of Spharodus gigas, 

 and a single curved palatal tooth of Pycnodus. Several teeth of 

 Pliosaurus and some teeth of apparently crocodilian character 

 also occur. 



The Oxford Clay has furnished four species of Ammonites, and 

 a phragmocone of a Belemnite ; and several vertebrae and teeth of 

 Ichthyosaurus and Plesiosaurus are also probably derived from this 

 formation. 



But the most interesting point that I have ascertained with re- 



