1 92 Rev. W. D. Conybeare on the Phenomena of Geology 



spread abroad by oceanic waves, like the gravel now lining 

 the beaches of our coasts : for it is clear that river courses 

 can only convey gravel over the lines of their channels, or 

 over the flats exposed to their floods. When therefore we find 

 gravel uniformly distributed over extensive plains which we 

 cannot conceive to have been in such a predicament,! see not 

 how we can avoid having recourse to oceanic waves ; indeed, 

 comparing the level of these beds with those of the posterior 

 rocks of submarine formation, (so far as the subsequent disloca- 

 tions and disturbances which have much deranged the relative 

 position of these strata will allow us to make the observation,) 

 we very generally find these masses of gravel deposited be- 

 neath what appears to have been the sea level at the epoch of 

 their accumulation. It certainly may be said, on the part of 

 the Fluvialists, that although the distribution of these gravel 

 beds must be referred to oceanic waves, still they may have 

 originated in the action of the rivers traversing the then 

 existing continents, and have been by these rivers transported 

 to the bed of that ocean. That this may have been partially 

 the case is, indeed, true ; just as it is with regard to the gravel 

 of our present sea-beaches. But surely in both instances it 

 must principally be referred to the more powerful agent, as 

 we must from the preceding argument be equally convinced 

 of the presence of " Earth-shaking Neptune" in both cases. 

 In the earlier period indeed, there is every reason to believe 

 that the currents of the then ocean must have been much more 

 violent than those which now exist, inasmuch as the disloca- 

 tions of the strata which appear then to have taken place, are 

 such as cannot be supposed to have occurred without having 

 occasioned the most impetuous waves and diluvial currents by 

 the impulse communicated to the circumfluent waters. 



The quartzose conglomerate of the millstone grit incumbent 

 on the carboniferous limestone occurs under circumstances 

 exactly similar, and in geological age so nearly approaches the 

 former, that it seems superfluous to separate it as indicating a 

 distinct diluvial period. 



2. The vast beds of conglomerate constituting very gene- 

 rally the lowest members of the new red sandstone, present a 

 still more striking instance of similar phenomena: they form 

 indeed, one of the most magnificent and illustrative oi all geo- 

 logical exhibitions. The materials of this conglomerate being 

 generally derived from the most contiguous chains of the older 

 rocks, vary in different districts : thus where the new red sand- 

 stone abuts against transition chains of grauwacke, &c. (as in 

 Devonshire,) the pebbles are quartz, hard slates, porphyry, &c. 

 (e. g. the celebrated Heavitree conglomerate) ; where the for- 

 mation 



