684 MR. E. CHAPMA.N ON THE BARGATE BEDS OF SURREY. [Nov. 1 894 



more or less gritty, the proportion of the oolitic grains in most 

 specimens being about one-third of the whole ; the other con- 

 stituents are the same as in the normal Bargate Stone. The 

 oolitic grains under the microscope resemble those of the Bath and 

 other Oolites, and sometimes exhibit the same radially crystalline 

 structure. 



Eig. 2. — Thin section of Bargate limestone with derived oolitic grains 

 and much quartz. Halfpenny Lane, Chilworth. x 21. 



At about the middle of the series of exposures on the west side 

 of this lane a bed of gravel may be seen, overlying the Bargate Beds, 

 and containing large angular fragments of the Bargate limestone. 

 This gravel-bed occurs at a height of 30 feet above the Tillingbourne 

 stream, as stated by K.. A. C. Godwin-Austen, and consists at this 

 spot of re-arranged Lower Greensand rock. 1 



From this gravel-bed I have collected many specimens of a 

 somewhat more purely calcareous oolitic rock. When examined 

 microscopically, this is seen to be composed of fragments of oolitic 

 limestone, forming a breccia, the pieces of limestone being very 



1 ' Along the several branches of the valley [of the Guildford Gorge] the 

 proportion of materials from the Lower Greeusand. increases.' Godwin- 

 Austen, Quart. Journ. Geol. Soc. vol. vii. (1851) p. 281. 



