562 OF QUICK-LIME

till a bed of them, of confiderable thicknefs,. was accumulated, might they not then be taken out in abundance to be employed as a manure? Thefe, if bruifed under a {tone like a tanner’s wheel, to reduce the fhells to{mall fragments, would certainly form as rich and efficacious a manure as could poffibly be devifed: nor could there be any difficulty in difpofing the ponds in in fuch a manner as to afford a conftant annual fupply.

It has probably been by a natural pro- cefs fimilar to this, that all thofe beds of fhell-marle we now meet with, have been originally produced. This fpecies of marle is generally found to confift of the fhells of this fort of{mall wilk, more or lefs de- compofed. The animals which inhabited thefe fhells have been once nourifhed by the water contained in thofe hollow places where this fort of marl is always found, and have probably been entirely deftroyed by fome accidental drought, which de- prived them of the water neceflary for their exiftence, or to fome other difaftrous circumftance that it is impoffible for us now to point out; and the thells remain-

ing

ee