105 



these fish defences belonged to these creatures. Such a fact shows us how little, 

 after all, we know of the Ufe of those early times, and how unwarrantable it 

 would be to assert that any particular stratum is the first in which a particular 

 fauna came into being — since though a good geologist is able from the pre- 

 dominance in certain particular rocks to identify them with very great precision, 

 and so his study may be said to assume the dignity of a science ; yet to 

 proceed to this further generalization would seem more than he is justified 

 in doing. 



And now we arrive at this more immediate neighbourhood where we 

 find the Mountain limestone, the Millstone grit, and the Coal measures 

 succeeding each other in their ordinary succession. The Millstone grit consti- 

 tutes that ridge which stretches out from the Titterstone to the N.E., where it 

 presents the appearance of a coarse conglomerate ; it is to be found also to 

 the S. and S. W. round this hiU. At the spot on which we stand, I 

 would call your attention to the basaltic rock, or, as it is locally called, Dhu 

 stone, which is here so extensively seen. There can be no doubt but that the 

 great blocks of stone upon which you are now reclining were at one time in a 

 state of fusion. It has been the custom up to late years to call a very great 

 variety of rocks igneous, such as the Granites, Gneiss, and Syenite. In obedience, 

 however, to that excellent law by which every scientific theory is open to question 

 and examination, and by which the mere dictiim of the learned is not sufficient to 

 decide its truth, there have been found some who are sceptical as to the wide 

 range of truly igneous rocks ; and it is now more than suspected that niunbers 

 of those which up to a recent date have been classified as such, are really of 

 sedimentary origin, altered or metamorphosed by certain chemical and physical 

 changes going on within them during the enormous periods of time which 

 have elapsed since their formation. Such is not, however, the case with the rock 

 iipon which we now stand. There can be no doubt that it was at one time 

 liquified under the action of heat, that it was protruded through the overlying 

 strata, and overflowed aU along that Hoar edge along which we have toiled up to 

 this spot, spreading itself out Kke a gigantic mushroom upon the surface of 

 the coal measures. The evidences that such is the fact, may be seen — 1st, in 

 the columnar structure which is to some extent observed in the rocks just 

 below us, called the Giant's Chair, and which, though not very visible to those 

 who approach the Clee-hills from the Ludlow side, is very striking to any one 

 who views it from the east ; 2ndly, the constituents of the stone itself, which 

 I am told proves its relation to known volcanic rocks ; 3rdly, that it has 

 actually been melted up by the application of heat, by which it becomes so 

 plastic and tractable as to render it capable of being cast into various forms, so 

 much so, that a manufactory to cast ornaments for architectural purposes out of 

 the Rowley rag was, I understand, some years ago started at Birmingham, but it 

 was found that their surface always became so yeUow when exposed to the air, 

 from the oxydizing of the iron it contains, that it has not been extensively used 

 for this purpose ; and lastly, it has been proved by actual experiment that a 



