IN THE MUD OF THE LEVANT. d 



revived by Mr. M'Culloch,* though in a some- 

 what untenable form. This hypothesis was con- 

 sidered to be open to several objections, — 

 especially when applied to such strata as the Chalk. 

 One was, that such an accumulation of broken 

 shells and corals, could scarcely be conceived to 

 consist of particles so minute and uniform as those 

 of the Chalk. Another, that any mechanical 

 action, as that of water, equal to the production 

 of such a degree of comminution, would also have 

 destroyed the sharp outlines of the imbedded 

 fossils. The same difficulties existed with 

 reference to many of the older limestones, but 

 less so to some of the coarse deposits of the 

 Oolitic Era. 



Analogous to this was the supposition that 

 many limestone strata had been vast coral reefs, 

 enclosing and alternating with calcareous sedi- 

 ments, produced by the abrasion of shells and 

 corals by the waves. f Though partly applicable 

 to some of the beds of the Coralline Oolite of 

 Yorkshire, yet this hypothesis when applied to 



* M'CuUoch's System of Geology. Vol. i. p. 219. 



t Lyell's Elements of Geology, p. 220. Many illustrative 

 facts are also recorded in the third edition of his Principles 

 of Geology. Vol. iii. p. 234, et seq. 



