Vol. 63.] KIMERLDGE CLAY AND CORALLIAN ROCKS OF BRILL. 31 



Ordnance map, contour-lines at intervals of 10 feet were sketched-in 

 upon the latter map, and from these the profile of the section was 

 obtained. The measurements in the brickfield were taken, partly 

 by means of the reflecting level, and partly by tape-measurement. 

 No attempt was made to measure horizontal distances in this case, 

 and consequently the representation of the details of the brickfield 

 is diagrammatic. 



At the top of the hill the Geological Survey has mapped Portland 

 Sands. There are fir-trees growing here, and many rabbit-holes 

 from which a sandy soil is thrown out, but it is by no means a 

 pure sand ; there are no ' lydite ' or other pebbles, and under the 

 microscope exceedingly few grains of glauconite can be detected. 

 At the old brickfield, less than a mile to the west, which formerly 

 exposed the junction of the Hartwell Clay with overlying strata, 

 there is recorded below the lydite-bed 3 feet of brown and greenish 

 mealy sand, followed by sandy Hartwell Clay. 1 These beds are 

 very probably represented at the top of Bid's Hill, but not the 

 lydite-bed itself, the pebbles from which could not fail to be seen 

 in the soil if it were present. 1 found no trace of Hartwell or other 



On the southern slope of the hill, about 90 yards from the top 

 and 27 feet below it, I found in April 1906 that a shallow well 

 had been dug. The material thrown out was a grey shale, with 

 many fragments of jet or black lignite (some nearly 2 inches 

 across). It yielded the following fossils : — 



Aptychus latus, Park. Ostrea sp. 



Exogym virgula, Defr. Cristcllaria, three or more species. 



These beds are evidently part of the Upper Kimeridge Clay, and 

 differ altogether in character from those in the brickfield described 

 below, being thorough shales instead of clays. 



In the brickfield at the northern foot of the hill there are, or 

 have been, exposed about 50 feet of clayey strata. The occurrence 

 in these clays of two bands of limestone makes clear the gentle 

 synclinal structure of which the clays themselves give more 

 obscure indications. Into this syncline the cutting has been made 

 symmetrically. The highest point of this section is about 50 feet 

 below the level of the exposure just described. 



The clays may be divided thus : — Feet. 



8. Grey, creamy- weathering clays (zone of Exogym virgula)... 4 

 7. Grey, creamy-weathering clays with crushed shells, be- 

 coming darker and slightly selenitic downwards and 



calcareous at the base about 17^- 



6. Band of creamy limestone 1 



5. Creamy calcareous clay 2 



4. Band of creamy limestone 1 



3. Dark grey, brown-weathering clay, with occasional phos- 



phatic nodules 8 



2. Black shaly clay, weathering lilac-grey with yellow stains, 



highly selenitic 14 



1. Band of grey limestone at the base, 6 feet below the floor of 

 the pit. ,. . ,.• 



1 H. B. Woodward, 'Middle & Upper Oolitic Eocks of England' Mem. 

 Geol. Surv. 1895, p. 221. This section has been obscure ever since I first saw 

 it in 1897, and the brickfield is now abandoned. 



