Great Coal-field of Shropshire, 207 



rocks between which it is at present found, and that to this intrusion 

 is owing the high elevation of the limestone ? But though the above 

 facts should be considered as justifying the hypothesis of the active 

 agency of the greenstone, and consequently its fluidity, I am by no 

 means prepared to affirm that this fluidity was that of igneous fusion; 

 for neither the sandstone, nor the limestone, nor even the crumbling 

 clayey marl appear to me to have undergone the smallest alteration 

 by the contact or close vicinity of the greenstone. 



The bed which lies immediately below the limestone and green- 

 stone is (as I have already mentioned) a soft, rather sandy slate-clay. 

 Its colour is bluish-brown and greyish white, and some of the strata 

 contain egg-shaped nodules highly impregnated with clay iron, 

 inclosing the impressions of marine remains. It is very shivery and 

 easy of decomposition, passing into a tenacious blue clay. On the 

 south of the Severn, along the bottom of Wenlock-edge, it may very 

 distinctly be seen supporting the limestone, and, like this latter, rising 

 west by north at an angle of about 8° ; but on the north of the 

 Severn, and especially in the vicinity of Little Wenlock and Steer- 

 away, its place seems to be taken by the greenstone already described. 



This bed rests upon another of considerable thickness composed of 

 a fine-grained soft micaceous stone of a dirty bluish-green colour, 

 passing into greenish-grey and ochre yellow. On inspection by the 

 lens it is manifestly a fine-grained mixture of green hornblende and 

 brownish felspar with numerous spangles of mica, and little or no 

 quartz. It is composed of strata which are alternately massive and 

 slaty, and in the latter the direction of the mica is strictly parallel to 

 that of the bed. That part of the bed which lies to the south of the 

 Severn is elevated at an angle of 37° rising N. N. W. and forms a 

 ridge of considerable height in the parallel of the Lawley and Caer 

 Caradoc, on which are situated the villages of Cardington, Church 



