128 Mr. Weaver on the Older Stratified Rocks of North Devon. 



Drawing then a distinction between original formation and 

 contingent derangements, between primary construction and 

 subsequent upraisings and depressions, if we look to the 

 terms of the series exhibited to us in the existing relations of 

 the constituent masses of our Continents and Islands, the vast 

 body of cumulative evidence supplied by the extended re- 

 searches of geological observers in general, among whom the 

 name of Lyell stands conspicuous, seem to leave little doubt 

 that the solid materials of the Shell of our Globe have under- 

 gone oscillatory movements in elevation and depression in re- 

 ference to the level of the sea. In some cases, these move- 

 ments appear to have been gently and slowly, in others vio- 

 lently and rapidly progressive, while subject to alternating fits 

 of comparative repose and energy, differing greatly in degree 

 and extent; thus corresponding with the successive differences 

 which are observable also in the position, composition, and 

 structure of rocks, and in the remains of the organized beings 

 by which they are respectively characterized*. 

 : But, in truth, let it be confessed, that, through whatever 

 means or secondary causes, acting during the course of a vast 

 Cyclef, the Great Architect of the Universe moulded the Sur- 

 face of the Earth by successive stages into its existing form 

 and condition, adapted to the habitation and p'urposes of man, 

 a scene fitted for the exercise and cultivation of his moral and 

 intellectual faculties : the full scope and application of those 



* I had at an early period (in the year 1818) con'ceived that the rela- 

 tive position of rocky formations, their general and subordinate structure, 

 their inflections, interstratification, and inclusion in each other, and their 

 frequent mutual connexion with contemporaneous and true veins, were 

 simply referable to the opposite powers of chemical affinity and mechanical 

 action, under the influence of hydrostatic pressure ; and not to an expan- 

 sive power from beneath^ Yet maturer reflection requires the admission, 

 that chemical action and an expansive power are, to a certain degree, cor- 

 relative, and not always in strictness to be disjoined j in other words, that 

 an expansive [)owcr, though not the cause of original formation, may have 

 been a concomitant, or one of the results. 



t This view, as to one vast Cycle, would seem to accord with the sug- 

 gestion of the Rev. W. Whewell, late President of the Geological Society, 

 expressed in his very able and profound work, the History of the In- 

 ductive Sciences. See vol. iii. on the two antagonist Doctrines of Geology, 

 p. 617 et seq. 



The same opinion, though perhaps not specifically expressed, would ap- 

 pear to breathe through the admirable address delivered by the Rev. Adam 

 Sedgwick, as President of the Geological Society, on the 18th February, 

 1831. And other names, of the highest distinction among our British 

 geologists, might, I believe, be also quoted, as impressed with the same 

 sentiment. 



1 Geol. Trans., vol. v. Memoir on the East of Ireland, §. 202. note. 



