Chap. III.] 
THE STIPER STONES. 
37 
CHAPTER III. 
LOWER SILURIAN ROCKS. 
ASCENDING ORDER OP THE STRATA PROM 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 OP 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 in 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 hilly 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 familiar 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-nags of Wales. Though in 
parts veined, altered, and fractured, and occasionally 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 the N.N.E. to Snead 
near Bishop's Castle on the S.S.W., or for a distance of upwards of ten 
miles, these siliceous 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 steadily their rela- 
tion to the Cambrian or Longmynd series on the east, and to their over- 
