THE SILURIAN SYSTEM. 



679 



rock, upon which the town of that name is built, the highest member of the Silurian 



system, consists of sandstone of various qualities, the grey strata of which are seen coming 



out from beneath the old red sandstone, along a zone extending through a hundred and fifty 



miles, from the hills near Ludlow on the north-east to the sea-cliffs of Pembroke on the 



south-west. At a short distance 



below the junction of the two 



systems, at Ludford, in the vi- '-^S^ 



cinity of Ludlow, upon laying tsSgacss^ 



open the rock for the foundation of a house, a stratum was 



discovered, abounding in the confused remains of fishes, which 



have also been found in various parts of the same deposit. The 



remains consisted of a matted mass of scales, teeth, and jaws ; 



and as no fossil relics of fishes had previously been detected in 



strata so ancient as the Silurian, or imagined to exist, the 



discovery of this bone-bed became of singular interest and 



importance. The engraving represents a few of these remains. 



According to M. Agassiz, 1, 2, 3. are probably fragments of 



the shagreen or skin of the same animal to which the tooth 4 



belonged. This, he remarks, " constitutes a new generic type, 



which may be designated by the name of Sphagodus, slaughtering 



or murderous tooth." Of the other teeth, he states, that " they cannot be referred to any 



species already known, and constitute a genus, the fishes of which were without doubt the 



pirates of the sea of that period." In association with the fish-bones, there was a " fucoid 



bed," according to the analysis of Dr.Prout, almost entirely made up of a multitude of small, 



wavy, rounded, stem-like forms, so completely resembling entangled sea-weed, as to 



induce the conjecture that they must be the impressions of such vegetables. 



In modern times, the Upper Silurians have in various spots suffered considerable 

 displacement through subsidences of strata, or landslips. The ancient chroniclers have 

 made the most of such events. " Near to the confluence of the Wye and the Lugg, to the 

 east," Camden relates, "a hill called Marley Hill, in the year 1575, rose as it were from 

 sleep, and for three days moved on its vast body, with a horrible noise, driving every 

 thing before to a higher ground, to the great astonishment of the beholders." But a 

 much more exaggerated statement occurs in Baker's . Chronicle : " In the 13th Queen 

 Elizabeth, a prodigious earthquake happened in the east part of Herefordshire, at a little 

 town called Kinaston. On the 17th of February, at six in the evening, the earth began to 

 open, and a hill with a rock under it, making at first a great bellowing noise, which was 

 heard a great way off, lifted itself up and began to travel, bearing along with it the trees 

 that grew upon it, the sheepfolds and flocks of sheep abiding there at the same time* In 

 the place from whence it was first moved, it left a gaping distance, forty feet broad and 

 four-score ells long, the which field was about twenty acres. Passing along, it overthrew 

 a chapel standing in the way, removed a yew-tree, standing in the church-yard, from the 

 west to the east. With the like force, it thrust before it highways, sheepfolds, and trees, 

 made tilled ground pasture, and again turned pasture into tillage* Having walked in this 

 sort from Saturday evening till Monday noon, it then stood stilL" Draytofl, in his Pol/-* 

 olbion, refers to this movement of Marley Hill:* 



" Inrag'd and mad with griefe, himself in two did rive ; 

 The trees and hedges neere, before him up doth drive, 

 And dropping headlong downe three daies together fall ; 

 Which, bellowing as he went, the rocks did so aphall, 

 That they him passage make, who cotes and chappels crusht, 

 So violentlie he into his valley rusht." 



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