218 THE GEOLOGICAL STEUCTUEE OF THE 



tion it has been removed entirely in half-a-mile from the 

 main road, and in an easterly direction it probably fails in 

 about three-quarters of a mile east of East Dundry. North 

 and south it is cut off by the escarpment. Consequently 

 the Ironshot Oolite occupies an area in the middle of the 

 hill only, and its extent cannot be more than 1| miles 

 long (from east to west) and about one mile wide (from 

 north to south). The reason for the limited east-to-w^est 

 extension of the Ironshot Oolite is in all probability de- 

 nudation subsequent to its deposition, to which the flat top 

 of the Ironshot itself bears witness ; and the planed-off top 

 of other beds, when the Ironshot Oolite is not present, also 

 tells the same tale. 



Above the Ironshot Oolite there is at Dundry a non- 

 sequence ; but at Oborne, near Sherborne, are found the 

 deposits laid down in this interval ; and these we have 

 noted in our Comparative Table, No. III. 



6. The Strata of the Bathonian Age. 



Of the date of the deposit which follows the strati- 

 graphical gap in the sequence of the Dundry rocks we 

 have a certain amount of evidence from contained fossils : 

 it was laid dow» during the GaraniiancB hemera. There- 

 fore it is contemporaneous with the Upper Trigonia-grit of 

 the Cotteswolds, which also follows the stratigraphical gap 

 so noticeable in that district ; and it is contemporaneous 

 with the Freestones of Sherborne (Dorset). 



Of the exact date of the later Dundry deposits we have 

 not much evidence. We have, of course, that of their 

 position in the stratal sequence, and we have the brachi- 

 opod evidence of the Coralline beds. 



