Chap. III.]                            THE STIPER STONES.
 

CHAPTER III.

LOWER SILURIAN ROCKS.

ascending order of the strata from beneath the stiper stones to the llandeilo
flags op shelve, in the original typical tract op the silurian region.—similar

order of strata in wales from the lingula-flags upwards.---the llandeilo rocks

and their fossils as exhibited in shropshire.—the range of the same formation
with its characteristic fossils through wales.—distinction between the llan¬
deilo and caradoc formations by infraposition and by fossils.—graptolites
exclusively silurian.

Let us now continue our survey, reverting to that district of Shropshire
in which, as has been shown, the Cambrian rocks are more largely de¬
veloped than m any other part of England and Wales, by examining the
fossiliferous strata which, resting conformably upon the upper ledges
of the Longmynd, have, from the period of my earliest researches, been
classed as the Silurian types. The lowest of these bands is seen be¬
neath the ridge called the Stiper Stones, than which there are few more
striking features in the physical geography of the British Isles. Trending
in a broken, mural line from N.N.E. to S.S.W., these stony masses appear
to the artist like insulated Cyclopean ruins, jutting out upon a lofty moor¬
land ridge, at heights varying from 1500 to 1600 feet above the sea. On
reaching the summit of this barren height, the traveller sees below him, to
the west, a rapid slope, and beyond it a picturesque hiUy tract, the strata
of which are laden with Lower Silurian fossils, and diversified by a variety
of rocks of igneous origin. In short, he has then within his view the
original type of formations which, raised to greater altitudes, and affected
by a slaty cleavage, occupy large mountainous districts in Wales.

The geologist who becomes famihar with the protruding bosses called
the Stiper Stones perceives that they are outstanding fragments of a thick
band of siliceous sandstones, resting upon dark-coloured schist, which I
consider to be the equivalent of the Lingula-flags of Wales. Though in
parts veined, altered, and fractured, and occasionaUy passing into crystal¬
line quartz-rock, the Stiper Stones yet form an integral portion of a great
schistose formation.

Extending from Pontesbury near Shrewsbury on th^N.N.E. to Snead
near Bishop's Castle on the S.S.W., or for a distance of upwards of ten
mUes, these sihceous rocks, together with their inferior black schists,
though subjected to several transverse breaks which have given slightly
divergent directions to portions of the chain, maintain steadUy their rela¬
tion to the Cambrian or Longmynd series on the east, and to their over-