208 Proceedings of the Royal Physical Society. 
ENGLAND. 
As the three divisions of the Coal-Measures—the Upper, 
the Middle, and the Lower—seldom occur equally well 
developed in any one coal field, I have selected for a short 
description of each, those coal fields where the general 
characteristics of the different divisions are well developed. 
We shall also find that between these three well-marked 
divisions, a Transition Series occurs in one case, which forms 
passage beds from the Upper to the Middle Coal-Measures. 
The Upper, Middle, and Lower Coal-Measures, as well as the 
Transition Series, are, however, very distinctly defined by 
their fossil plants. 
Upper CoaL-MEASURES. 
Typical Avrea.—The Radstock and Farrington Series 
of the Bristol and Somerset Coal Field. 
This field occupies a basin-shaped hollow, and its extreme 
length from north to south is 26 miles, and from east to west, 
if the outlying Nailsea basin be included, 24 miles. If the 
Nailsea basin be excluded (and it is omitted from the follow- 
ing notes), its width, from Bath in the east to Bristol in the 
west, is reduced to 12 miles. 
The Somerset Coal Field is mostly Spain by Secondary 
rocks. 
The succession of Palzeozoic rocks from above downwards is: 
Secondary Rocks. 
Palezoie Rocks: 
( Radstock Series. 
| Farrington Series. 
| Coal-Measures. { Pennant Rock. 
} New Rock Series. 
\ Vobster Series. 
Carboniferous - 
Millstone Grit. 
| Carboniferous Limestone. 
Old Red Sandstone. 
The Coal-Measures are separable into two divisions. 
An upper division céntaining— 
(a) Radstock Series. 
‘arri Sl Upper Coal-Measures. 
(>) Farrington Series. § PI al-Mez 
