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LITHOLOGICAL STRUCTURE OF THE CARADOC TRAP. 



the one from the other. These different substances will be first described, and it will 

 afterwards be shown, that amorphous masses made up of these materials have dislocated 

 and highly altered the adjacent strata. 



In the Lawley we find compact felspar rock passing into hornstone; felspar rock occasionally co- 

 loured green by chlorite ; fine-grained syenite with and without olivine ; amygdaloid having a base 

 of purple felspar and hornblende, more or less intermixed with green earth, which from a simple rock 

 passes into one in which the amygdaloidal structure prevails, the globular concretions consisting 

 chiefly of glassy, greenish yellow, radiated actinolite, with some green earth, calc spar, and quartz. 



This is the beautiful amygdaloid first described in Dr. Townson's " Tracts," and again mentioned 

 by Mr. A. Aikin, Geol. Trans., 1st series, vol. i. p. 210. It was supposed to be peculiar to the 

 north-western face of Caer Caradoc, but I have discovered it near the summit of the Lawley, in the 

 Little Caradoc, and in Hope Bowdler Hill, &c. It may therefore be considered common to the 

 range. 



Little Caradoc. — 'Felspar rocks as in the Lawley ; greenstone containing numerous crystals of 

 white glassy felspar. 



Caer Caradoc. — Compact felspar rock is in great abundance as in all the other hills ; the most 

 beautiful variety is cellular, the cavities varying in size from that of a small almond to a pin's head 

 and all compressed. 



These cells are lined with minute hexahedral prisms of quartz mixed with a greenish yellow, 

 earthy matter, perhaps decomposed actinolite ? This rock is penetrated by veins of quartz, flesh- 

 red felspar and chalcedony, the latter of which fills all the cells of the adjacent rock (Aikin, p. 210). 

 The Caer Caradoc also contains greenstones of several varieties, some of which are so fine-grained 

 as almost to pass into basalt 1 . In Haslar, Uelmeth, and Ragleth Hills, there are ill-defined green- 

 stones, with felspar rock, claystone, &c. 



Hope Bowdler. — Rocks of compact felspar near Woodgate Bowdler, coloured green by chlorite, 

 the red felspar giving to them a mottled aspect. Parts of these rocks have a bedded appearance 

 and a steatitic feel, and in some specimens plates of green earth alternate with laminae of pink 

 felspar. 



In a gorge leading from Woodgate Bowdler to the Battle stones, the compact felspar is slightly 

 porphyritic j another rock has a base of compact felspar and hornblende, with crystals of common 

 felspar, thus indicating a passage into greenstone. 



At the knotty points called the "Battle stones," which stand out on the western face of the Bowd- 

 ler Hills opposite to Caer Caradoc, is seen a trap conglomerate including concretions of compact 

 felspar, quartz, green earth, and minute scales of talc. Another variety at this wild and rugged spot, 

 is a compound of small grains of quartz, in a base of compact felspar, tinged green by green earth. 



This range of hills presents many well developed cases of changes in the structure of 

 the adjacent sandstone, which have been effected by the trap. 



For instance, we may follow the strata of the Caradoc sandstone, full of fossils, as 

 they range by Chatwall and Enchmarch to Cardington, where they are cut in upon 

 by the great mass of unstratified trap rocks, of Cardington and Hope Bowdler Hills 



1 In a most instructive collection of rocks from these hills made by the Rev. J. Yates some specimens are 

 considered by him to be true basalt. (Museum of the Liverpool Institution.) 



