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to be explained by those who advocate this view was the absence 
of Millstone Grit, which ought to occur between the Mountain 
Limestone and the Coal Measures. “No trace (he says) of this 
has been observed around any one of the three patches of 
Limestone” (p. 151). And in a note he refers to a 
letter from Mr. MecMurtrie corroborating that view, or at least 
the view that Millstone Grit had not been detected between 
the Limestone and Coal Measures. Well, time goes on, these 
difficulties. set brains thinking and hands working, and four 
years afterwards Mr. McMurtrie contributed to this Club one 
_ of those admirable and careful papers for which we have been 
hitherto so much indebted to him, ‘‘ On Certain Isolated Areas of 
Mountain Limestone at Luckington, Vobster, &c.,” read December 
9th. 1874.* In these he brings forward facts, if not decisive 
of the question, yet contributing much towards our information 
on the subject. After describing the features of the district, 
he discusses the fault and anticlinal theory of Woodward and 
the “ overthrow” theory of Moore and others. As to the fault 
theory, he shows that subsequent workings have proved that 
these faults do not exist so as to account for the upheaval of 
the Limestone through the Coal Measures. And in considering 
the overthrow theory he states that coal has been worked 
beneath these Limestone patches, which he thinks have been 
folded over from the range of the Mendips. Bus he states 
(p. 291) that after carefully examining all the three patches he 
had been unable to discern in situ either Millstone Grit on 
the one hand or Mountain Limestone shale on the other, but 
that in a field to the north of Vobster Limekiln he had 
found on the surface numerous stray blocks of Millstone Grit; 
not distinguishable from the same beds in Mells Park, and 
hints at the possibility that portions of this Grit may be in situ 
not far distant. 
* Vol, III., No, 3, of our “ Proceedings,” 1877. 
