502 



MESSES. "WHITE AND TBEACHEK ON THE [Aug. 1906, 



with a rich brown vermiculate crust and greyish-green nucleus, are 

 scattered sparingly through the rock. 



The lowest chalk visible in the main exposure is similar to that in 

 the trial-hole, save that the hard lumps are much scarcer, the brown 

 grains and nodules more numerous, and the nodules attain a greater 

 size (three-quarters of an inch). 



Fig. 2. 



N.E 



-Section on the south side of pit (a), about a quarter of a mile 

 north-west of Winterbourne Church. 



[Vertical scale : 1 inch =20 feet.] 



Near the top of bed (1) the hard lumps reappear in force, and 

 the brown granules, increasing in number, impart to the rock the 

 characteristic dusty-grey tinge of Phosphatic Chalk. Neither here 

 nor in any other part of the section, however, do the beds contain 

 nearly so great a proportion of phosphatized material as the brown 

 chalks of Taplow and Lewes. 



The ascertained thickness of bed (1) is 8J feet. 



The chalk above described passes up into a hard, yellowish- 

 green, nodular rock — bed (2) — about 3 inches thick. This band is, 

 in places, sufficiently homogeneous to have acquired a rectangular 

 jointing ; elsewhere it consists of rounded lumps and nodules, sepa- 

 rated by rather softer chalk containing many small brown nodules 

 with furrowed, perforate crusts. Impressions of sponges are 

 common. 



The succeeding- bed (3) is a white to pale-grey, exceedingly- 



gritty, friable chalk, between 4-, 



and 4| feet thick. 



and somewhat 



widely jointed. Oyster-shelis form no small proportion of the bed, 

 and the weathered surfaces are rough with their remains. Brown 

 nodules ranging up to three-quarters of an inch in diameter, and 

 brown angular concretions of smaller size are abundant ; but there 

 is a decided f alling-off in the proportion of brown granules. Towards 

 the top this chalk becomes firmer, assumes a lumpy character, and 

 passes, sometimes insensibly, sometimes rather abruptly, into the 

 overlying hard band. 



The hard chalk of bed (4) is a tough limestone, 6 to 9 inches 

 thick, of a yellow or greenish-yellow hue, but stained dull red in 

 places by iron-oxide, which occurs in subspherical pseudomorphs 

 after pyrites. Greenish nodules (to 3 or 4 inches in diameter) 

 with brown corrugate crusts, and angular concretions (under half 



