32 . II. RELICS. Introduction 



at the bottom of the sea, could be accomplished: 

 and that this, at last,, must have been effected by a 

 gradual attachment of mineral particles (such as 

 the ocean then abounded with ) to the surface of 

 these floating leaves, stems, &c. Thus inducing in 

 each individual,, that degree of specific gravity ne- 

 cessary for its subsidenc eand final deposition,, in the 

 depths of the ocean. 



b. 14. Ancient lakes and inlaiid-seas . To the 

 agency of these,, during the second period, are per- 

 haps to be referred all depositions of vegetable bo- 

 dies and fluviatile shells, embodied in deep and re- 

 gular strata, and not mixed with marine remains, 

 also, in some instances, those deposits of plants, 

 &c., in which marine bodies very sparingly occur. 



To these agents also, but during the latter part of 

 the second period, are to be ascribed many of those 

 deposits of vegetable matters, which occur in less 

 deep or regular strata, and which occasionally ex- 

 hibit the remains of mammalia, without any mixture 

 of sea-shells or other marine exuvite. 



Obs. On the retiring of the ocean from our con- 

 tinents, no doubt, extensive lakes and inland-seas 

 were left in the hollows and depressions of the ori- 

 ginal strata. The waters of these lakes, &c., 

 would for a time retain the nature of the sea, of 

 which they once formed a part ; and hence, the 

 mixture of marine remains in their primary depo- 

 sits. In process of time, from the deposition of 

 the matter first held in solution, and from the con- 

 tinued influx of fresh water, the nature of these 



