240 CHALK AJJD FLINTS. 



period necessary for that, and also for the deposita- 

 tion in the places where it is found, must have been 

 considerable ; and nothing but an action of the sea 

 could have given the surface the form which it still 

 has, notwithstanding all the action of art and of the 

 weather. 



But though we could explain by the action of 

 river and estuarial resistance, aided by the winds, 

 all the formation of these alluvial strata, we are not 

 a jot nearer the formation of solid rocks than ever. 

 Nay, when, as we must, we have recourse to the 

 action of the sea, even though that sea had con- 

 stantly outraged the angry monsoon at the Cape, or 

 out-eddied the Bay of Biscay, the whole process 

 would be change rather than formation the de- 

 struction and breaking down of rocks, and not the 

 consolidation. Even if the chalk is sea- shells, and 

 the flints are sponges, a goodly pressure must have 

 been required to bring them into their present state ; 

 and therefore to seek for their origin, we must exam- 

 ine downwards into the deep. 



What the condition of the sea was, when it covered 

 all the land, for, whether all at the same time or 

 not, the sea must have covered all the land, and 

 covered it to a great depth at some time or other, 

 we cannot say. The mountain limestones would 

 lead us to suppose that it contained shelled animals 

 of some kind or other, long before one foot of the 

 dry land appeared above its surface ; and the oolites, 

 and many other formations, leave not the least doubt 

 that they were under the waters, inasmuch as they 

 contain shells, and skeletons, and entire fishes, which 

 are adapted for the deep water. 



The mean level of the sea may be taken as the 

 line of greatest fertility both in the water and on 

 land, and both in the animal and the vegetable king- 

 doms, because it is the line of the greatest action 

 of both the sun and the air. It is probable that the 

 sea sinks down as much below that line in propor- 



