1870.] ETHERIDGE—DRISi0L DOLOMITIU CONGLOMERATE. 185 
tertiary times—and cannot doubt, from the physical condition of 
the vales of the Severn, Gloucester, and Berkeley, &c., that the 
finely exposed western escarpments of Oolite, and still more east- 
ward ranges of Cretaceous rocks, in fact the whole Secondary series, 
once covered and arched over the now deeply exposed and denuded 
Lower Mesozoic and Paleozoic rocks that constitute the mass of the 
country west of the Cotteswold range. What influence and changes 
these valleys underwent still later, or during the Pliocene and Post- 
pliocene epochs, I would leave to be discussed in a special paper upon 
the age of the Severn valley. 
I believe, then, that it was during the progress of the denudation of 
the paleeozoic rocks by the seas of the Triassic epoch that the pre- 
existing faults and fissures, or open joints, &c., along the coast-lines, 
were mechanically and chemically filled in. The colour and 
nature of the New Red marls and sandstones, fully attest the pre- 
sence and abundance of the peroxide and protoxide of iron at the 
time of their deposition, due perhaps originally to the oxidation 
of the materials contained in the older carboniferous rocks, which 
became thus metamorphosed during removal and deposition. The 
chemical condition of the saline waters, or even water at a higher 
temperature than that of the modern seas of Europe, may have 
tended to the more rapid deposition or accumulation of the iron &c. 
in the faults and fissures. 
There are many localities in and around the Bristol coal-field 
where full and complete evidence can be obtained as to the age of 
the infilling of these dislocations &c. in the Carboniferous Lime- 
stone, Millstone Grit, and Pennant, due to the destruction of the 
older rocks by that sea which also deposited the conglomerate and 
associated New Red series. 
At Broadfield Down, south of Bristol, Providence Place, near Ashton, 
many places on the Mendip Hills, as well as north-west of Bristol, 
along the west side of the coal-basin, where the hydrous oxides of 
iron are worked, the broad and exposed surfaces of the limestone 
and grits are planed away and laid bare; and here and there in the 
depressions pockets occur, the remains, or remnants, of the earliest- 
formed portion of the dolomitic conglomerate. So also with the 
fissures and faults which are usually filled with the magnesian 
breccia, the cementing matrix in many cases being the brown and 
red hydrated peroxides of iron as well as the dolomites, the qualities 
and quantities of the ore differing with the matrix or rock in which 
it occurs. Doubtless the percolation of water through porous over- 
lying strata highly charged with the oxides of iron, as is the case 
with the New Red series, has also been a source and mode of accu- 
mulation ; and this phenomenon or mode of production is now in 
operation along the lines and in and upon the walls of the great 
Ram Hill and associated fault that traverses the northern coal-basin, 
as, notably, at Frampton Cottercll. 
It is, however, to Clifton that my paper has chief reference, as 
I am desirous of fixing the exact position of the locality where the 
remains of Thecodontosaurus and Paleosaurus were discovered by 
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