172 EEV. A. IRVING ON THE STEATIGEAPHY 



under the green-earth series again, only to crop out in the Cali- 

 fornia brickyard. This settles the horizon of the clays at that 

 place. (See below, Sect. Q.) 



Section P. Clay-pit at Wick Hill, Finchampstead. 265' O.D. 



feet. 



a. Pebbly run of the hill 2 



b. Loamy sand with green grains in rough layers 4 



c. Dark green earthy sands with very distinct seams of 1 o 



purplish clay J 



[Layer of bog-iron-ore here.] 



d. Stiff clay, strongly laminated deep purple and choco- "1 ^ 



late-coloured, black and more shaly below J 



e. Stiff clay, drab-coloured, laminated, with patches of 1 ^ 



green giauconitic sand J 



f. Brown irony loam with much green giauconitic sand | n 



in subordinated layers, and irony nodules j 



g. Sand (proved to) 2 



Total of section 28 



Two small pits dug this winter at rather different levels on the 

 other side of the hill have exposed the drab-coloured clay e of 

 this section at the same altitude (at a distance of 250 yards) with 

 5 or 6 feet of normal green sand above (= bed d). Taking 

 this into account, with the occurrence of patches of the same 

 green sand in the beds of e and /, we may regard the beds 

 c to g of this section as a local phase of the green-earth series 

 (Nos. 7 and 8), the clays being developed at the expense of the 

 green earths *. 



Section Q. Clay-pit in California Brickyard (330 yards 

 nortTi-east of P). 



feet. 

 a. Sandy drift 2 



h. Coarse sands with seams of strong grey clay, marked "j 

 by very pronounced current-bedding with a nor- I 6 

 therly false dip of nearly 3°t J 



c. Mild clay (brick material), more sandy below, strongly 1 



laminated, with no appreciable dip in good sec- I 20 

 tions at right angles (215-235', O.D.) J 



d. Grey-green dirty quartz-sand (proved in 2 wells) 6 



Total exposure in pits and well-sections 34 



The plentiful supply of water in the wells here points to the 

 probable presence of London Clay at no great depth. The car- 

 bonaceous character of the under strata {d) is confirmed by the 

 character of the water, its action on iron J, and analysis in my 

 laboratory. In a sand-pit a little way to the north, in the wood, 



* Compare Section M, where a simUar lateral transition is noted. 



t I doubt this being an Eocene deposit without excavating further into the 

 hill. 



\ Cf. Geol. Mag. for September 1883 and January 1885: papers by the 

 author on " Water Supply." 



