18 



of the petrifying substances, both concerning the mineral 

 strata in which they were imbedded, and the nature of the 

 countries in which they were found. The flinty Echini 

 most generally indicate the chalk formation a formation 

 which we observe to form low and flat districts on the east 

 coast of England. Encrinites mineralized with calcareous 

 spar, we most frequently find in the limestones of the coal 

 formation, which form low and fertile countries, varied only 

 by gentle elevations of the strata, or interrupted by abrupt 

 projections of trap rocks, as in many of the secondary 

 lime-stone districts of Scotland. The external aspect of the 

 skeletons of Fishes, from the Paris gypsum formation, is 

 very different from that of the fresh-water fishes of the 

 bituminous marl-slate, independent of their zoological 

 characters. 



The branches of Natural History we have hitherto men- 

 tioned, as connected with or illustrative of Zoology, relate 

 only to bodies of a simple composition, and whose pheno- 

 mena, depending on the ordinary affinities of matter, exerted 

 at insensible or at perceptible distances, admit of rigorous 

 explanation on chemical principles, or are regulated by the 

 laws of mechanical philosophy. The composition of organ- 

 ized bodies is more complex : they assume more regular 

 and determinate forms, the affinities of their component 

 elements are more nicely balanced, and they exhibit a 

 series of phenomena, for a definite period, too complicated 

 to be explained in the present state of science, either on the 

 principles of Chemistry or Mechanics. From numerous 

 experiments, Naturalists have been led to believe that the 

 simplest organized bodies, as Monads and Globulin^ ori- 

 ginate spontaneously from matter in a fluid state, and that 

 these simple bodies, of spontaneous origin, are the same 

 with the gelatinous globules which compose the soft parts 

 of Animals and Plants. Many of the phenomena of Plants, 

 as the absorption of moisture by their roots, the respira- 

 tion of the leaves, their turning in the direction of the sun, 

 and the passage of fluids through their inert tubes, are 



