217 



OOLITE GRAINS IN THE UPPER LIAS OF 

 GRANTHAM. 



H. PRESTON, F.G.S., and A. E."TRUEMAN, M.Sc. 



Oolite grains are found occasionally in the limestones of the 

 Lias, as for example, in the ironstone of Frodingham, North 

 Lincolnshire, and in the upper bed of marlstone at Chipping 

 Warden, Northants. They are not, however, of common 



*> fi «5 







w.3 



Fig j —Compound grain X 15. Fi g 2.— Enlarged portion of Fig. 1 a. 

 (p = Tubule. v = Radial structure). X 3 2 



Figs. 3, 4. — Typical grains. x 15. 



occurrence in the clays of the upper Lias, although they have 

 been recorded in certain beds in Northamptonshire.* 



Comparatively large oolite grains are by no means uncom- 

 mon in a bed of clay, about a foot in thickness, exposed in 

 Rudd's brickyard, south of the railway station, Grantham. f 



* B. Thompson, ' Northamptonshire.' Proc. Geol. Assoc, 1910, p. 461. 

 t H. Preston. Pvoc GeoL Assoc, 1905, p. 114. 



1917 July l. 



