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The first distinct departure from the fault theory of which I 
have any knowledge occurs in a paper read before the North of 
England Institute of Mining Engineers at Birmingham, in 1866, 
by Mr. G. C. Greenwell, who, during his residence in Somerset- 
shire, contributed a number of valuable papers on the local 
Coal-field. He then expressed the opinion “that the same 
“convulsion which threw over the Coal Measures threw masses of 
“Limestone along with them, and those marked on the geological 
“map of the Ordnance Survey are not, as there represented, the 
“result of the faults ingeniously placed there, but masses detached 
“from the Mendip range of Limestone situated about a mile to 
“the south.” He also said that “men now living have worked 
“in coal beneath these masses of Mountain Limestone.” 
In 1866 and 1867 we find the subject dealt with by Mr. Charles 
Moore. In his paper, “ On Abnormal Secondary Deposits,” in 
the latter year he referred incidentally to these Limestones, and 
discarding the idea of an upheaval he regarded the overthrow 
theory as an established fact. 
Tn an essay on the Coal-fields of North Somersetshire in 1867, 
and some published correspondence which followed it, the same 
view was maintained by Mr. S. W. Brice, who suggested “ that 
“when the Mendip range was considerably higher than it is now, 
“masses of Limestone might easily have een dislocated from their 
“parent rock, and have rolled down a species of inclined plane 
“into the positions they now occupy.” The plans by which he 
sought to establish the point, however, were, not sufficiently 
accurate, and some of his arguments were, in my opinion, open to 
objection. 
Probably the latest writer on the subject has been Mr. Horace 
B. Woodward, of the Geological Survey, a gentleman to whom we 
have been indebted within the last few years for many interesting 
articles on the geology of this district. In a paper published in 
the “ Geological Magazine,” for April, 1871, he altogether dissented 
from the overthrow theory, and maintained that these areas of 
