225 
ON the probable existence of coal mea- 
sures IN THE SOUTH-EAST OF ENGLAND. 
By JOSEPH PRESTWICH, F.R.S., F.G.S. 
[PLATE LXXXV.] 
T HE question of discovering coal in the south-east of Eng- 
land, so long treated in an empirical manner, has of late 
years assumed a scientific aspect, but in a direction entirely 
different from that towards which practice pointed. So many 
of our Tertiary and Secondary strata contain thin beds of lignite 
and shale, together with beds of sandstone — the first sometimes 
not unlike impure coal, and the latter resembling the shales 
and sandstones of the Coal Measures — that it is not surprising 
that men, ignorant of scientific modes of investigation, and at a 
period when geology was little understood, should have been 
misled by resemblance of parts into a belief of identity of the 
whole. But the progress of geology has since conclusively 
shown that although certain beds of lignite of Miocene and 
Wealden age may be worked for such purposes as lime-burning, 
and some beds of fair coal are wrought in the Oolites, as at 
Brora in Sutherlandshire, yet to all practical intent the beds of 
good and workable coal are confined to certain strata, known as 
the Coal Measures, forming the upper part of the palceozoio 
series of rocks, the position of which is perfectly well defined, 
and the organic remains of which serve to render their deter- 
mination a matter of certainty. 
The imperfect lignites of our tertiary strata around London ; 
the lignites and sandstones. of our Wealden area; the clays of 
the Jurassic series, have all at times given rise to the search 
after coal in the strata far above the Coal Measures ; while the 
sandstones of the Devonian and the shales of the Silurian 
series have given rise to equally abortive attempts amongst the 
rocks under the true coal measures, even up to a recent period, 
by so-called practical men. 
Aubry gives a curious account of one of these searches after 
coal, made in the neighbourhood of Guildford, at the end of 
VOL. XI. — NO. XLIV. Q 
