Vol. 57.] THE BAJOCIAN OP THE NORTH C0TTESW0LD8. 143 



is no evidence that they do ; and actually it better fits the facts that 

 they do not. 



In the early part of the paper I noted the considerable develop- 

 ment of the Snowshill Clay, Tilestone, and Harford Sands. My 

 field-measurements (admittedly incomplete) assigned to them a 

 minimum thickness of 50 feet. Now that I have drawn the diagram, 

 I can understand that a thickness of 100 feet may be possible. At 

 any rate, a considerable development of these beds in the Kineton 

 area exactly fits : (1) the persistence of the Notgrove Freestone; 

 (2) the syncline between Eowell Gate and Donnington ; while the 

 syncline accounts for the much greater rapidity of the disappearance 

 of strata in the Bourton-on-the-Hill neighbourhood than in the 

 Cleeve-Hill district. 



A further remark may be made. The present height of the 

 Marlstone above sea-level is very nearly the same on the west flank 

 of the North Cotteswolds as on the east flank overlooking the 

 Moreton Yale : it is in close approximation to the 600-foot contour- 

 line. But the level of the Upper Trigonia-grit is very different. 

 It is more than 1000 feet above sea-level on the west flank, and 

 it is about 700 feet above sea-level on the east flank. If then 

 the Upper Trigonia-grit was laid down on a level surface, as shown 

 in the diagram, then at that date the Marlstone dipped westward 

 from the Yale of Moreton, and was some 300 feet lower on the 

 west flank than on the east. The Tertiary elevation of the country 

 brought the Marlstone up to be nearly level, and tilted slightly 

 the Upper Trigonia-grit. 



In fig. 3 the present contour-lines are drawn askew. By placing 

 these contour-lines horizontally, the present-day position of the 

 strata may be observed. By placing the Upper Trigonia-grit line 

 horizontally, the position of affairs at the time of the deposition 

 of that bed will be seen, and that is the position which the 

 diagram is designed to illustrate. 



I would now draw attention to the great difference that exists 

 between the west-to-east section of the Cotteswolds which I have 

 given, and that put forward by Hull and other authors, wherein a 

 gradually progressive diminution, not only of the Inferior- Oolite 

 rocks, but of Middle and Lower Lias, is assumed. 



(e) Comparison with Prof. HulFs Section. 



In the sections given by Hull ^ there are the following results, 

 approximately : — At Leckhampton, Inferior Oolite 230 feet, Upper 

 Lias 200, Marlstone 120, Lower Lias (partly shown) said to be 600 

 feet (ojp. cit. p. 15) — the total about 1150 feet ; but at Burford the 

 whole, from the top of the Inferior Oolite to the (assumed) base of 

 the Lower Lias is made only 150 feet. This extraordinary result 

 is supposed to constitute the thinning-out of the Jurassic rocks 

 to the eastward. It has been generally accepted, for H. B. Wood- 



^ Mem. Geol. Surv. 1857, ' Geo!, of Country around Cheltenham' pi. ii. 



