Chap. XIII.] 
PERMIAN KOCKS IN ENGLAND. 
329 
2nd, a great mass of the thick-bedded magnesian limestone j 3rd, a zone of red 
marl with gypsum ; 4th, the thin-bedded limestone so largely worked in York- 
shire, and which, containing traces only of magnesia, is preferred for agricultural 
purposes ; and, 5th, red sands and marls, which range up to the town of Don- 
caster, and form the summit of the whole group. But, to return to the con- 
sideration of the basement-rock of the group. 
Obscured by overlying formations and detritus in the North Riding of York- 
shire, the red and yellow sandstones emerge in force between Ripon and Knares- 
borough, and under the Castle at the last-mentioned place are surmounted in a 
striking cliff by the Magnesian Limestone, precisely in the same manner as in 
Durham, the lower part of the yellow rock being underlain by a thick-bedded, 
deep-red, hard, sandy grit. In this district, indeed, and particularly on the 
banks of the Nid near Knaresborough, the inferior red member rises up in 
marked and distinct physical masses, which there merge into an angular and 
subangular quartzose conglomerate, undistinguishable from the Roth-liegende 
of the Germans. Whilst revisiting these scenes of my youth in the autumn 
of 1857, in company with Mr. Aveline, immediately after a tour in the Thiirin- 
gerwald, Harz, and Bohemia, I had no hesitation in affirming that the well- 
known picturesque 1 Plumpton Rocks ' near Harrogate are identical with the 
quartz-conglomerates of Germany (pp. 316 &c), whether as regards their ingre- 
dients, colour, false-bedding, or massive stratification. 
In tracing the lower sandstones southwards through Yorkshire, they are seen 
to be quarried in many places to the west of Bramham Moor ; and at Pontefract 
they are largely worked. There the yellow 1 Pontefract rock ' * is again clearly 
seen, as in Durham, to form the natural base of the Magnesian Limestone. 
The lowest visible beds at Pontefract are also occasionally of a red colour ; 
but the great mass of conglomerate and breccia, as exposed in the Plumpton 
Rocks, is no longer to be detected, the bottom beds being simply hard, deep- 
red, flaglike, micaceous grits f. These are surmounted by yellow sandstones, in 
parts of whitish colours, which are extensively used as building- and trough- 
stones, some portions being so porous as to make excellent filters. Occasionally, 
indeed, the stratum is so incoherent as to be used only as scouring-sand. 
To the south of Pontefract the lower sandstones, both red and yellow, begin 
to thin out ; and, though they are recognizable on the banks of the Don, and 
under the Castle of Conisborough, the band is greatly reduced in thickness, and 
exhibits little more than a reddish, micaceous, flaggy rock, with shale &c. 
Still further to the south, this lower sandstone, as exposed on the eastern side of 
the Pennine chain, and to the east of the South Yorkshire Coal-field, is dimi- 
nished to a mere bed, which expires altogether in the environs of Nottingham. 
There the Magnesian Limestone rests at once upon the Coal-measures. 
Thus this lower member of the Permian group, as seen on the eastern side of 
the Pennine chain, exhibits, though on a less scale, the chief peculiarities of its 
German equivalents. In One place a fine sand, in another a coarse grit, in a 
third a breccia or conglomerate, and always varying much in dimensions, it has 
evidently been formed on the eroded surfaces of the preexisting Carboniferous 
rocks. But however variable in thickness it may be, as depending upon the 
method of accumulation, we invariably perceive that its upper beds graduate 
into and form the natural bottom of the Magnesian Limestone, as formerly 
* So named by William Smith, the ' father' of in the G-eol. Mag. vol. iii. p. 49, in which he gives 
English geology, whose lessons in the field along his reasons for regarding these sandstones as a 
the Yorkshire coast (1826) were of great service part of the Millstone-grit, demands our best atten- 
to me. tion, but does not alter my opinion. 
t The clear and careful paper by Mr. Binney, 
