UPPER PORTION OF DUNDRY HILL. 203 



There are three noticeably ironshot beds at different horizons — Nos. 5, 

 19, and 22 — but they are all very different both in lithic characters and 

 in the fossils they contain. This is a matter of importance. 



The Marlstone Rock outcrops in the bank of Spring Farm 

 rickyarcl, in the middle of East Dundry, and, as it forms a 

 small feature, it may be traced along the valley below the 

 exposure of the Ironshot Oolite. 



This outcrop is a point of very considerable importance. 

 It is evident that the officers of the Greological Survey mistook 

 this rock, which is an ironshot oolite, for " the Ironshot 

 Oolite," the noticeable fossiliferous bed of Dundry Hill, 

 whereby they confused the bottom bed of this Section with 

 a bed which is 70 feet above it. Then, acting on this suppo- 

 sition, and knowing there would be so much of the " Inferior 

 Oolite " below the " Ironshot," they drew the base-line of 

 the " Inferior Oolite " somewhat below the outcrop of the 

 Marlstone Rock, with this result — that they have coloured 

 in their map as " Inferior Oolite " not only areas occupied 

 by what they call "Midford Sands ^' or "Upper Lias" in 

 other districts, not only Middle Lias, but even in all likeli- 

 hood a part of what they would term Lower Lias. And in 

 this way they have made the Inferior Oolite in places — for 

 these remarks apply to most of the hill — nearly 150 feet 

 thick : that is, from where they draw their line up to the 

 top of the hill. The " Inferior Oolite " base-line should 

 have been drawn at the base of No. 17, about 15 feet 

 below the outcrop of the Ironshot Oolite ; whereas it is 

 drawn in the Geological Survey maps some distance below 

 the outcrop of bed 22 — in fact, nearly 100 feet too low 

 down. 



The bed No. 14 is hard and massive— very distinct from 

 the rubbly condition to which the other rocks of the Rackle- 

 down exposure have been reduced. It was certainly de- 



