56 
same, viz., that the carboniferous formation probably existed as: 
an elevated ridge “which for many ages proved a barrier to the 
incursion of the deeper sea deposits which were taking place to. 
the south, and’in which weré being accumulated the materials. 
composing many of the Secondary rocks.” 
Coat MEASURES. 
In comparing the Coal Measures of this neighbourhood with 
those of France and Belgium, there is great difficulty in obtaining 
such particulars of the latter as are necessary to draw a proper 
comparison. 
The Coal Measures, as they exist in Somersetshire, consist of 
the following well marked divisions :— 
Seams. os of 
Radstock Series Hehe Ft. 
Upper Division | Red Shales \ 2,200 
Farrington Series Arenas 
Pennant rock, barren ... aoe Sc 3,000 
New Rock Series nce ae! 1 
Lower Division { Voie Series... sate 48 2,800 
Barren ground J 
38 8,000 
Millstone Grit... bet ace wae a 500 
Carboniferous Limestore and Shales aa! eae 3,600 
Total eee Soe « 12,100 
ee 
and it would be interesting to know whether similar subdivisions 
exist on the Continent. 
In his report to the Royal Coal Commission, to which reference 
has already been made, Professor Prestwich has pointed out that 
in comparing the coal measures of South Wales with those of 
Somerset he found the same triple arrangement to prevail, due to 
the presence in both of the great mass of sandstone known as the 
Pennant Rock, and he found the total thickness of Coal Measures 
in the two districts to be nearly equal, but in minor points he 
