Vol. 52.] ON THE UPPER PORTION OF DUNDRY HILL. 717 



forming a steep and well-marked escarpment on the northern and 

 western faces of the hill, and a very bold one above the valley west 

 of East Dundry and round the Maes Knoll promontory ; but this 

 feature is much less clearly defined, and often quite indistinct, on the 

 southern face of the eastern portion of the hill and round the Hackle- 

 down projection. The greater hardness of the rocks of Bathonian 

 age (to which date, it is to be remembered, we assign the Freestones 

 of Dundry), relatively to the underlying deposits, gives a steeper 

 slope to the upper edge of the escarpment, so that we generally find 

 a projecting brow of these rocks above the somewhat softer strata 

 of Bajocian-Aalenian date. It is often hard to define with pre- 

 cision the base of the ' Upper (Bathonian) beds,' partly owing to 

 the limited number of exposures at the right level, and partly 

 because much of their rubble has travelled some distance down 

 the hillside, concealing the outcrops of the underlying strata. 



The strata of the Bajocian-Aalenian ages, which are also a variable 

 series, owing in part at any rate to pre-Bathonian denudation, form, 

 where they are present, the lower and generally less steep upper 

 portion of the escarpment, or even a slight terrace. 



The Dumortieria-clixys, deposited during the Toarcian age, are 

 readily worn back, and hence they usually give a very steep, sometimes 

 almost mural slope beneath the overlying protecting beds. Slopes 

 of this kind are found beneath Dundry village, and around the Maes 

 Knoll promontory. 



At a distance of from 50 to 60 feet below the lower limits of the 

 strata of the Bathonian-Aalenian ages, a second lower and minor 

 escarpment or terrace may frequently be noted. This escarpment is 

 determined either by the Marlstone llock, by the ' bifrons-hed,' or by 

 some hard beds in the lower portion of the Dumortieria-cl&ys a little 

 above that bed. The feature made by the Marlstone Rock is often 

 well defined in the eastern portion of the hill, e.g. at various points 

 along the northern escarpment east of the northern end of Xewdown 

 Lane, directly beneath East Dundry, and around the upper portion 

 of the East Dundry Vale. 



Below the Marlstone terrace the ground formed of soft clays of 

 the Charmouthian age, with few hard beds in them, slopes away at 

 a much gentler angle than the clay ground above the Marlstone 

 slopes down to that rock. 



It may be noticed that the beds of Dundry are synclinal, espe- 

 cially from east to west. This synclinal feature probably accounts 

 for the lower level at which the strata of the Bathonian age lie near 

 East Dundry compared with Maes Knoll. On the edges of the 

 escarpments there is evidence of local faulting or slipping over, as 

 for instance at Barns Batch, and the northern main roadside quarry : 

 while dip-slope towards the escarpments, and not any exaggerated 

 thickness of the beds, probably accounts for the much lower level 

 which the strata of Bathonian age (Coralline, etc.) occupy on the 

 edges as compared with the middle portion of the hill — as, for 

 instance, the northern and north-eastern margin of the main hill, and 

 the eastern slopes of the Rackledown spur. 



