260 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [JaU. 23, 



Ostrea, small species. Rostellaria ? 



Pectunculus Plumsteadiensis, Sow. Teeth of Lamnse. 



Pyrula tricostata, Desk. 



Hence this bed may be traced by Old Basing, Odiham, Farnham*, 

 to Guildford, where an interesting section of it was exposed on the 

 line of railroad a few hundred feet north of the present station. 

 (See fig. 6.) 



Fig. 6. — Section at Guildford. 



fBro^rn London clay mthout fos- 

 sils, passing downwards into 

 yellowish sand, and then into 

 "e," mixed yellow sand and 

 clay and green sand ; full of 

 round flint pebbles, but without 

 organic remains. 

 Yellow sandy clay full of shells, 

 perfect and in fragments {Cy- 

 rena, Cerithhim, and Ostrea). 



2. Very dark clay mottled red. 



3. Light greenish clay mottled 

 red, passing down into mottled 

 clays of different colours and 

 sands. 



The junction with the chalk is not exposed. The outcrop of this 

 latter is however seen a few yards nearer Guildford. This section is 

 of much interest from the circumstance of a thin layer (1 of c?) of 

 the fluviatile shells of the Woolwich beds occurring on the top of the 

 mottled clays and under stratum "c." This is the most westerly 

 point at which these shells have, I beheve, been yet observed. They 

 consist of several species of Cyrena, Cerit?iium, and Ostrea. The hne 

 of separation between beds *'c" and "^" is waved and irregular. 



Passing by Leatherhead, Epsom, and Ewell to Croydon, no good 

 section of this bed is exhibited ; indications of it occur only here and 

 there. It then trends suddenly to the north, but still it is not exposed 

 until we reach Lewisham, where, in one of the pits near the summit 

 of Loam-pit Hill, the London clay, with a thin basement conglo- 

 merate bed, may be seen overlying a bed of light-coloured sand. (See 

 fig. 7.) 



Fig. 7. — Section at Loam-pit Hill. 



a. Brown clay mixed with flint gravel. 



b. London clay; laminated brown clay with septaria oc- 

 casionally. No organic remains yet found. 



c. Round flint pebbles in brown clay, and in places sand. 

 No organic remains. 



d. Light yellow and whitish sa 



8 to 10 feet exposed. 



The pits lower down the hill show in disconnected sections the 



* Two miles W.N.W, from this to^Yn T have recently found in a brook above 

 Lower Old Park Farm, detached blocks with numerous fossils of this " Basement 

 bed." 



