ON THE DELUGE, 



665 



usually found within a few feet of low water ; some at least 

 of the number being identical with living species. 



If the square miles of solid land in which those myriads of 

 shells are now embedded, had been upheaved (as geologists say),' 

 either gradually, or rapidly, shells could not be found there in 

 their present confused and compressed state. Had the land 

 sunk down many thousand feet with shells upon it, they 

 might have been covered with mud, and on being afterwards 

 upheaved again they would have appeared embedded regularly 

 where they grew, in a matrix which, with the pressure of a 

 superincumbent ocean, might have flattened and penetrated 

 them : but they would not have been torn away from their 

 roots, rolled, broken, mashed, and mixed in endless confusion, 

 similarly to those now in my possession. 



There is also another consideration : geologists who con- 

 tend for the central heat of the earth assert that substances 

 subjected to great pressure under the sea become altered: 

 hence, in conformity with their theory, these shells could not 

 have been long buried under a deep ocean, and afterwards 

 raised in their pristine state. So little changed are these shells, 

 except in form, that they appear as if they had been heaped 



water. The specific gravity of oyster shell, when dead, is about twice 

 that of sea-water (2092,1 028). Most other shells are rauch lighter, and 

 but few at all heavier than the oyster. 



Before ending this note I must remark that the horizontal movement 

 of water near the bottom, though gentle, may tend to press together and 

 smooth any loose sand, mud that sinks, oazy clay, or fragments of shells, 

 before many of their particles travel far. Water in rapid motion is 

 known to hold sand as well as mud in suspension, but not shells, unless 

 the current is very strong. To such a constant agitation of the sea, 

 oscillating gently with each tide, we may perhaps ascribe the com- 

 paratively level and smoothened state of the bed of the ocean, Avhere 

 it has hitherto been sounded. Excepting near irregular, rocky land, 

 one finds, generally speaking, no ravines, no vallies, no abrupt transitions 

 in the bottom of the sea. For miles together there is an almost equal 

 or gradually altering depth of water : and little similarity can be traced 

 between the contour of the bed of a sea and the neighbouring dry land, 

 until you are near the shore, where the sea acts differently, and irregular 

 bottom is as frequent as it is usually dangerous for shipping. 



