732 PEPORT—1899. 
This area is partly Westphalian and east of the Rhine, followed west by the 
coalfields of Aix-la-Chapelle and Liége; the great east and west fields of Hainaut, 
comprising Namur, Charleroi, and Mons; then succeeded west by the prolific 
coalfield of Valenciennes, in the Pas-de-Calais, 
That these coal basins were originally connected, and extended from the 
Rhine and Eastern Belgium to Somersetshire immediately north of the Mendip 
Hills, is now admitted. 
Their mean thickness, where taken in their most complete series, shows similar 
results, as given in the following table :— 
Mean Thickness of the Five Great Coalfields. 
Bristol | Hainaut, cfs : 
South Wales | oomerset (South) | Chaslerol, and Liege Westphalia 
10,000 ft. 8,400 ft. | 9,400 ft. 7,600 ft. 7,218 ft, 
It is important to notice also in tabular form the number of coal-seams and 
the workable thickness of the same. 
South Bristol Hainaut, | 
= W Flee Somerset Charleroi, | Liege Westphalia | 
(South) and Mons | 
Number of seams of 75 55 110 85 117 
coal | 
Total thickness of 120 ft. 98 ft. 230 ft. 212, 294 ft. 
workable coal | 
One probable cause of the greater amount of coal in these Continental coalfields 
as compared with the two British areas where the Pennent is only developed, as in 
the South Wales and the Bristol coal-basins, arises from the fact that the so-called 
Pennant Rock, which is from 2,000 feet to 3,000 feet thick in the Bristol and 
South Wales coalfields, and containing but little coal, is replaced by the more 
productive Coal Measures, with workable coal, in Belgium and North France. 
Again. the general characters of the groups of ccal seams have often a distinc- 
tive element amongst themselves, such similarity being maintained in all essential 
points throughout Belgium, North France, and Britain; this persistence of the 
eame physical character both in South Wales, Somerset, and Gloucestershire is a 
condition most important to note; and although the South Wales coalfield is 
separated from the Bristol basin by 80 miles, yet in the mass and general structure 
they show strongly marked and definite physical features and relations. 
Table of Comparison between the Two Basins. 
Coal Measures of South Wales Coal Measures of the Bristol Coal basin | 
5 ( Sandstones and shales 3,400ft. | # 
&J with 26 seams of thick af Sandstone teed ae 
5 | coal St wi seams of coa thic 
3 (penne Sandstone 8,260ft. | < ( Pennant Rock Sandstone 3,000 ft. 
AS Rock with 15 coal thick Ss with 4 or 5 seamS of thick 
= | seams Ss | coal 
# ( Shales and sandstones 400-1,400ft. | 4 (Shales and _ sandstones 2,800 ft. 
5 and ironstone with thick z with ironstone and 28 thick 
8 34 seams 8 seams of coal 
8,060 ft. 8,400 ft. 
Ss a ae 
