16 
POPULAR SCIENCE REVIEW. 
early in the Silurian epoch. This hill is only one of a chain 
twenty miles long, but it is selected as the one most carefully 
studied by the writer. 
The Wrekin is about two miles south-west of the town of 
Wellington. It rises sharply up from the Triassic plain of North 
Shropshire, and stands out as the advanced guard of the nume- 
rous ridges which intersect the southern half of the county. 
But it is six or seven miles distant from the main groups, and 
its isolation gives it great prominence. It is only 1,320 feet in 
height, but it is said to be the highest mountain in Europe for 
the circumference of its base. The range of which it is the 
most conspicuous elevation is three miles in length, trending 
north-east and south-west, and is cut into three separate masses 
by two deep and narrow gorges. The Wrekin proper is one 
mile and three quarters long, and about half a mile in breadth 
at the base. Its shape is peculiarly graceful. Viewed from 
almost every point its outline forms an unbroken curve. From 
the north-west it appears like a quarter moon resting on the 
earth with its convexity upwards. From the south-west it pre- 
sents the outline of a perfectly symmetrical arch. The legend 
runs that this arch was piled up by an industrious giant. 
Science tells us that it was originally thrust up between two 
parallel dislocations or faults as a gigantic wedge, and was sub- 
sequently rounded into its present elegant form by the busy 
fingers of frost, carbonic acid, and rain, working unceasingly 
through immeasurable ages. 
No authentic account of the origin of the Wrekin has yet 
been published. A pseudo-scientific description from a local 
guide-book of the birth of the mountain is little less mythical 
than the legend of the giant’s arch. The- reader is gravely in- 
formed that “ when the struggling gases below the Silurian 
ocean made an effort to be free, a power of indescribable force 
shook the earth, upheaving the ocean bed and throwing up 
precipitous hills above the waves ; and so, amidst boiling waters, 
hissing steam, and exploding gases, the Wrekin and its adjacent 
hills rose to their present elevation.” 
The account of the structure of the Wrekin in Murchison’s 
“ Silurian System” is more rational, but it is equally erroneous. 
The mountain is described as a mass of disruptive greenstone 
forced up into the midst of Caradoc sandstone and shale, and 
altering the sandstone into the hard white crystalline rock called 
quartzite. This account of the Wrekin is endorsed by the 
Geological Survey, whose map and sections of the district were 
published during the time Murchison was Director General. 
According to this hypothesis, the mountain is necessarily 
younger than the Lower Silurian strata on its flanks. But no 
terms could more unfitly describe it than “disruptive green- 
