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speculation, and different authorities have arrived at very opposite 
conclusions on the subject. At a recent meeting of the Somerset- 
shire Archeological and Natural History Society the question 
gave rise to much discussion without leading to any very definite 
result, and it is well deserving of further inquiry. It is hoped 
the facts brought forward in the present paper, if they do not 
settle the question, will add to the information already possessed 
on the subject. 
Descriptive Notes.—In order to convey a clear idea of the position 
of these Limestones and of their relation to the surrounding 
strata, I have prepared a diagram on a scale of forty inches to the 
mile, to which I would direct your attention.* 
The principal outcrop of Mountain Limestone in the district 
under consideration occurs in the Mendip hills, which are flanked 
by it continuously on both sides. The northern slope of those 
hills between Whatley and Leigh-on-Mendip forms the base of 
the diagram, and the Limestone is there seen dipping uniformly 
to the northward at an angle which Mr. Sanders has recorded as 
70 degrees, but in places the beds are almost perpendicular. 
The lower slope of the Mendips is occupied by the Millstone 
Grit, which can be traced continuously along the base of the hills 
as shewn in the diagram, but it is seldom well exposed on the 
surface and the prevailing inclination is very difficult to ascertain. 
In some instances it dips northwards conformably with the Lime- 
stone, but at other points there are indications of reverse dips, 
leading to the conclusion that it has been folded over during the 
elevation of that range. 
Proceeding Northwards from this belt of Millstone Grit, we 
enter the principal basin of the Somersetshire Coal Measures, 
which are here extensively exposed on the surface, although to 
the North East they soon pass beneath the secondary rocks. In 
the very midst of these Coal Measures, and far separated from 
* See a reduced copy of this diagram appended to this paper. 
