Mr. J. F. "Walker on a Phosphatic Deposit. 381 



rison of specimens; and the sutural space of the Australian 

 species is never so deep or concave as in its European prototype, 

 in which also the plaits on the columella are very much less 

 conspicuous and more oblique, the anterior one alone approach- 

 ing the size of the four on V. anticingulatum. The spire has 

 one sculptured whorl, fuller than in the V. cingulata of Ger- 

 many. There is no living species like it. 



Very abundant, with occasionally the /S variety and more 

 rarely the a variety, perstriata, in the Tertiary sands of the 

 Bird Rock beds. Ad. 22 to 21, less so in Ad. 23. Both varieties 

 common in the sandy beds Ad. 24. 



XL VIII. — On a Phosphatic Deposit in the Lower Greensand of 

 Bedfordshire. By J. F. Walker, F.C.S., Sid. Suss. College, 

 Cambridge*. 



[Plate XIII.] 



The Lower Greensand formation in Bedfordshire consists of 

 extensive beds of variously coloured sands, more or less indu- 

 rated into stone. 



In the vicinity of Sandy there exists a conglomerate which it 

 is proposed to discuss in this paper. A short account of this bed, 

 by the Rev. P. B. Brodie, appeared in the ' Geological Magazine ' 

 for April. I sent a short paper on the discovery of some fossils 

 in it to the 'Annals and Magazine of Natural History* for July; 

 Mr. H. Seeley this month (August) also communicated his views 

 on this bed in a letter to the Editors of that Magazine. 



This conglomerate was formerly quarried for mending the 

 roads, until two or three years since, when it was discovered that 

 it contained nodules of phosphatic matter, for which it is at pre- 

 sent extensively worked. At a cutting near the Potton Railway 

 station the bed is from 9 inches to 1 foot in thickness; and the 

 following is the section, the strata here being slightly inclined. 



1. Sand of different colours, in some places white. 



2. Conglomerate bed, 9 inches to I foot in thickness. 



3. Sand of various colours, containing layers of oxide of iron, 12 feet. 



* Communicated by the Author, having been read before the British 

 Association, in Sections B. and C, at Nottingham, 18(56. 



