1870. ] ETHERIDGE—BRISTOL DOLOMITIC CONGLOMERATE, Lei 
immediate Bristol area, and in the West-Somerset and South- 
Wales districts, convince me that the age of this conglomerate was 
the coming in or commencement of the Keuper in the area under 
consideration. 
I must not omit also to state that Sir H.De la Beche in 1846 *, 
and subsequently in his ‘ Geological Observer’y, discussed this ques- 
tion and clearly defined the geological position and conditions of the 
dolomitic conglomerate. He has successfully shown that it was in- 
tercalated with the associated and succeeding sandstones and marls at 
many places, and during different periods, in and through the 
Keuper series, and even continued up to and may have included 
the base of the Lias;”’ but we must guard against misunderstanding 
the two conglomerates, their paleontological contents being totally 
different. 
There are many localities along the north side of the Mendip 
Hills, on steep or rising ground, where the intermingling of beach- 
like wedge-shaped masses with finer surrounding and associated 
sandstones constantly occurs, these finer accumulations not having 
been (in some places) removed by denudation, Again, we nme 
doubt that the superincumbent marls and sandstones cover up or 
conceal enormous masses of widely spread conglomerate. This is 
especially the case over the upper coal-shales in the centre of the 
southern coal-field. The surrounding zone of Pennant and Lower 
Coal-shales, Millstone Grit, and Carboniferous Limestone also suc- 
cessively have their upturned edges more or less covered by the con- 
glomerate, the so-called “ millstone” or ‘‘ overlie ” of the coal-miners, 
as is proved by almost every coal-pit sunk in the southern basin; 
and the contents of the breccia or conglomerate at once determine 
the source of the pebbles. 
The Geological Survey of Great Britain, in their published hori- 
zontal sections, have also distinctly shown, over the Mendip area, the 
recurrence of masses of conglomerate during the deposition of the 
whole Keuper series, and how not one only, but many beds of breccia, 
&e., with similar phenomena and under given conditions, occur along 
the strike of the palzeozoic land, having been deposited throughout the 
whole time that the Keuper sandstone and marls were accumulating 
in a deeper or more open sca. 
3. Mone or OccURRENCE. 
To appreciate this fringe or existing remnant of a once widely 
spread mass of conglomerate nearly surrounding the Gloucestershire 
and Somersetshire coal-basin, it should be seen and examined in situ. 
It has now the appearance of a line of consolidated shingle 
beaches remaining at their old levels with relation to the palw- 
ozoic rocks on which they rest and from which they were origi- 
nally constructed. They represent an amount of time so yast, 
and a mass of old and lost land so great, that the mind almost re- 
* Mem. Geol. Surv. vol. i. 1846. 
+ Geological Observer, 1853, pp. 476-496. 
