318 E. 8. COBBOLD ON THE EXPOSED STRATA OP THE 



this, again, was a stratum of very sandy limestone 2 feet 6 inches 

 thick, suggesting a trace of the Upper Calcareous Grit. 



Then followed compact Kimmeridge Clay, containing vertebrae of 

 Pliosaurus and quantities of crystals of selenite, also at the end of 

 the section near the surface a marly layer with some good specimens 

 of RTiynchonella inconstans. The inclination of the base of the Kim- 

 meridge Clay was ascertained to be 1 in 60 in the direction of the 

 road (S.S.E.), which would give a thickness of 20 feet at the end of 

 the section. 



At the junction of the Kimmeridge Clay with the Coralline Oolite 

 was a peculiar, bright-red, earthy layer from 4 to 6 inches thick. 



A section at right angles to this along the lane leading from the 

 south end of fig. 2 to the farm was also exposed, and is given in 

 fig. 4 ; but it was too shallow in the lowest part of the road to show 

 the junction of the clay with the marls, which, it may be noticed, 

 again show long undulations, and rise to a higher level than the 

 clay, implying either a very sharp bend in the strata or a fault 

 through the lowest point of the section. 



On the west side of the sewage-farm is a quarry sunk through 

 the base of the marls to the shell-bed below, which is used for road- 

 making. A vertical section here (fig. 6) shows the shell-bed and 

 sand resting on the Calcareous Grit, with the marls above. Where the 

 latter are within 3 feet of the surface they are much contorted and 

 mixed up, so as to lose their original bedding, and here and there 

 are balls or nodules of brown clay (probably foreign to the marls) 

 surrounded by concentric layers of darker and lighter material. 



As considerable quantities of stone were required for making 

 roads, it was hoped that the same bed might be found on the other 

 side of the farm ; and several trial-holes were sunk with this special 

 object. 



At no. 1 (fig. 8) a layer of concretionary stones, similar to that 

 in the sand of the railway- cutting at 12 feet 6 inches below the top 

 of the Grit, was found. 



At no. 2 (fig. 9) the shell-bed is shown, but here it has dimi- 

 nished in thickness to about 1 foot, and as there was a considerable 

 quantity of water in the sand, it was not worth working. 



At no. 3 (fig. 7) it was hoped that the Coralline Oolite would 

 be found as in Sandford Hill; but on sinking through the clay, marl 

 was at once found, with only two layers of stone 1 foot and 6 inches 

 thick respectively. It was also of a blue colour, similar to that in 

 Sandford Hill. 



Subsequently a small quarry was opened (at C, fig. 3), close to trial- 

 hole no. 1, which exposed a quantity of Eoman pottery. Several kilns 

 have since been found here, and in order to show the proximity of 

 the Kimmeridge Clay, the section (fig. 3) was constructed. It has 

 never been wholly exposed, and is therefore somewhat hypothetical 

 as to inclination of strata ; but it was proved in many places by 

 subsequent excavations, and may be taken as tolerably correct. 



The inclination was arrived at by setting off below the shell-bed 

 in trial-hole no. 2 a depth of 12 feet 6 inches, which was supposed to 



