SUBTERRANEAN GEOLOGY OF SOUTH-EASTERN ENGLAND. 147
it, to that of deep borings through the Secondary rocks. Those
bearing upon our subject are, with one exception, in South-eastern
England, the exception being the boring at Burford on the western
border of Oxfordshire. There is thus a gap in our boring evidence
between Burford and Richmond, a distance of between 60 and 70
miles, which we may hope will some day be much diminished.
It will be best on many grounds to consider this Burford boring
first. A glance at a geological map shows us that Burford stands on
rocks of Lower Oolitic age, and is about 35 miles due east of the
Forest of Dean coalfield, and rather more than 30 miles due north of the
eastern end of the Vale of Pewsey. Mr. H. B. Woodward ("Geology
of England and Wales," Ed. 2) gives the following abstract of this
Burford boring :—
Coal-measures were thus entered at a depth of 1,1 84 feet. They
are evidently an easterly continuation of those of South Wales, Bristol,
and Forest of Dean coalfields, which, originally continuous, are
now broken into separate basins. Looking at the respective dis-
tances of the Bristol and Forest of Dean coalfields north of the
Mendip Hills, and that of Burford from the Vale of Pewsey, it seems
likely that the Burford coal basin lies mainly south of that town, and
was touched on its northern edge.
We now come to the borings near or east of London. Godwin-
Austen's paper was read, as I have already stated, on May 30th, 1855.
Among his concluding remarks are the following :—"It will not be
deemed too much to say that we have strong a priori reasons for
supposing that the course of a band of coal-measures coincides with,
and may some day be reached along the line of the valley of the
Thames, while some of the deeper seated coal, as well as certain over-
lying and limited horizons may occur beneath some of the longi-
tudinal folds of the Wealden denudation." The reference to the
"deeper seated coal" in the latter part of the above sentence arose
from the belief of Godwin-Austen at the time it was written that the
Hardinghen coalfield in the Boulonais was not on the same
geological horizon as the Basin of Namur, but on a lower one, a