482 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 2, 



the Estuarine Drifts. I shall now endeavour to advance reasons 

 sufficient to account for the following facts : — 1st. Why this penin- 

 sula, terminating in Ebrington Hill, has been preserved, while the 

 contemporaneous strata which once overspread the Vale of Moreton 

 have been swept away ; and, 2nd. Why this, together with the 

 majority of the headlands of the Cotteswold Hills, project in a 

 northerly direction. 



I believe there is evidence to prove that the principal headlands 

 are in lines of gentle synclinals ; while the lateral valleys which 

 bound them run in the directions of anticlinal axes, or have a qua- 

 quaversal arrangement of the strata. When a series of comparatively 

 hard and indestructible beds rest upon a much thicker series of strata 

 of an opposite character, and preserve an approximate horizontality, 

 it is evident that, when a slight elevation or anticlinal arrangement 

 of the beds has been produced along a line of country, the axis will 

 create a line of least resistance, and that a valley will be formed when 

 the area is subjected to the action of the sea ; and conversely, that a 

 corresponding synclinal axis will produce a line of greatest resistance, 

 tending to the formation of a headland under the same circumstances. 

 Under such conditions do the headland of Ebrington Hill and the 

 Vale of Moreton appear to have originated. 



The strata of the Cotteswold Hills are, in general, except when in 

 proximity to lines of fault, so nearly horizontal, that the existence of 

 a dip must often be proved rather by a process of reasoning than by 

 actual observation of the bedding, as seen in natural sections and 

 quarries. Now, it is well known, that in cases of escarpments the 

 ledges range parallel to the strike of the rocks, and consequently that 

 the flanks have an aspect in an opposite direction to the dip of the 

 beds. Hence we conclude from analogy that the flanks of the pen- 

 insula of Ebrington Hill dip towards the centre ; — along which there 

 must therefore be a synclinal axis. In the present instance, how- 

 ever, we are not driven to deduce the existence of a synclinal alto- 

 gether from analogical inference. Along the eastern escarpment 

 there is decided evidence of a westerly dip, because the lower beds 

 of the Oolite occupy a higher level along the ridge than they do in 

 the centre of the area to the westward ; and the same phsenomena 

 are generally observable with regard to the beds along the opposite 

 side of the peninsula. 



If it be allowed that a synclinal axis exists along the peninsula 

 of Ebrington Hill, it follows, almost necessarily, that an anticlinal 

 traverses longitudinally the Vale of Moreton. (See fig. 3.) I have 

 not had the opportunity of examining the oolitic ridge which bounds 

 the vale along the eastern side, but we may safely conclude that 

 a slight dip to the eastward is maintained along its flank. As the 

 vale is some ten miles in width at its widest part, a dip in opposite 

 directions of one degree would elevate the beds about 500 feet * 

 in the centre of the vale above their present position along the 

 flanks ; and the base of the Oolite would be placed at an elevation 



* Let = angle of inclination = 1° ; r = radius = 5 miles or 8800 yds. ; and cc = 

 answer. Then x= (log r+log sin 0) — log cos 0= 153*6 yds. or 460-8 ft, (nearly). 



