OF CREATION. 215 



of them having been extracted from a few quarries 

 of Tilgate grit, opened for road-making and for the 

 supply of rough stone for building purposes. There 

 is no reason to suppose that the species in question 

 was confined to this locality, or was more abundant 

 there than elsewhere, nor that it was limited to 

 the Wealden district as exhibited in the south-east 

 of England, where, it must be remembered, the 

 strata have a vertical thickness of not less than a 

 thousand feet. 



It is, no doubt, difficult to confine the imagina- 

 tion within due bounds when we endeavour to re- 

 call scenes enacted during the earlier periods of the 

 earth's history, and to picture these past events with- 

 out running into extravagance, and without over- 

 stepping the limits of simplicity and probability, 

 which should always characterise natural history. 

 I will, however, notwithstanding the difficulty and 

 danger, venture now, in concluding this chapter, to 

 shadow out to the reader a few descriptive scenes, 

 which may serve to give a better definition to the 

 views he may have derived of the remarkable geolo- 

 gical epoch described in the present chapter. 



I think there is no doubt that we ought to regard the 

 whole of the oolitic series from the lias to the chalk 

 as one distinct period involving many great changes, 

 but still well marked throughout by its own group of 

 vegetables and animals successively developed or suc- 

 cessively introduced. Taking this view, we may recog- 

 nise in the vast variety of created beings thus grouped 

 together, one unbroken series, affected from time to 

 time by local circumstances and conditions ; and I 

 venture, therefore, to picture the various members of 



