COAL MEASURES IN THE SOUTH-EAST OF ENGLAND. 233 
Again, M. Mengy, in 1852,* remarks : “ However it maybe, 
the considerable thickness of the overlying unproductive strata 
( terrains morts) which exist in the western part of Belgium 
and Department du Nord, shows that there is a great depres- 
sion there, which is a prolongation of the deep subterranean 
substrata above which London stands, and if a coal measure 
basin exists there, which is not impossible, they may extend to 
the southern border of that depression, which reaches near to 
Lille, and may be connected more or less directly with the vast 
carboniferous system which comes to the surface in England, 
rangingfrom Wales to Scotland.” 
But it was not until 1855, when Mr. Godwin- Austen f 
brought the question before the Geological Society in an able 
and elaborate paper, accompanied by a map, in which he showed 
that the coal measures which thin out under the chalk near 
Theronanne probably set in again at or near Calais, and are 
prolonged (beneath the tertiary strata and the chalk) in the 
line of the Thames Valley, parallel with the North Downs, and 
continue thence under the valley of the Kennet, into the Bath 
and Bristol coal area, that the attention of geologists was 
seriously directed to the subject. Reasoning also on theoretical 
considerations connected with the extension of the old coal- 
growth in the west of Europe, Mr. Godwin- Austen concluded 
that “ coal measures might possibly extend beneath the south- 
eastern part of England,” and he showed, upon well-considered 
theoretical grounds, that the coal measures of a large portion of 
England, France, and Belgium were once probably continuous, 
and that the present coal-fields were merely fragments of a great 
original deposit, which he inferred had been broken up in two 
directions previously to the deposition of the secondary rocks. 
He endorsed also the opinion that the main line of dis- 
turbance had a general east and west direction — that part of 
it formed the great anticlinal of the Ardennes, by which the 
Belgian coal-field had been tilted up, and brought to the sur- 
face — and that the Mendips with the Somerset coal-field are 
on the same line of strike. 
These views have been controverted by some distinguished 
geologists, but they have received the assent of a greater 
number ; and the information we have since acquired of the 
thickness of the secondary strata and of the existence of palaeo- 
zoic rocks at Kentish Town and Harwich , i and the discussion 
* u Essai de G^ologie Pratique sur la Flandre Fran 9 ais,” 1852, p. 76. 
t u Quart. Journ. Geol. Soc.,” vol. xii. p. 83. 
f For detailed particulars of the strata at these wells, see the papers hy 
the writer in “ Journ. Geol. Soc.,” vol. xii. p. 6, and vol. xiv. p. 249. 
