The Rev. W. Buckland on the Plastic Clay Formation. 287 



No. Feet. 



12. Striped sand, yellow, fine, and iron-shot - - - 10 



13. Alluvium * -...'---- — 



Total 91 



At a point still higher on this hill than No. 12, is a thick bed of 

 dark blue clay, without shells, which is used to make tiles and bricks, 

 and which appears to continue upwards from this brick kiln to the 

 summit of the hill, forming a thick cap over the sands and clays 

 mentioned in the section, and is probably an outlying hummock of 

 the London clay, separated only by a small valley from the exten- 

 sive mass of that stratum which is found two miles south-west in the 

 Sydenham hills , and being placed between and connecting them 

 with the London clay of Shooter's hill.f 



* In this alluvium four large and entire tusks of elephants were discovered a few years 

 ago, in a garden opposite the chalk pit, at the base of Loam Pit Hill, and on the north 

 side of the turnpike road ; they soon perished by exposure to the air, but were for some 

 time in the possession of Mr. Lee, the owner of the extensive brick works on Loam Pit 

 Hill, to whom I am indebted for this information. 



+ Mr. Webster mentions (Geol. Trans, v. 2, p. 235) that rounded flints are found in the sand 

 strata, at the bottom of the blue or London clay, in several parts of the London basin. And 

 again (p. 185), that the abundant supply of water which is constantly found in boring 

 through the same clay, indicates an extensive deposition of three beds of sand. The 

 sandy strata containing pebbles, and the watery sand thus alluded to appear to be the 

 continuation of the upper strata of the plastic clay formation, and connected with those 

 of Loam Pit Hill. 



In the shaft at the northern extremity of the tunnel under the Thames, near Rotherhithe, 

 these same beds were found, covered by more than 30 feet of London clay, although 

 from their rapid rise under the bed of the Thames towards the south, the shaft on the 

 south side (of which Mr. Webster has given a section, p. 197) exhibits only nine feet 

 of this clay incumbent on the watery gravel and subjacent beds of the plastic clay for- 

 mation. 



A curious section is preserved in Sir C. Wren's Parentalia (p. 285), obtained in pre- 

 paring the foundations of the present cathedral church of St. Paul, in London. 



2 o 2 



