164 III. DIST. CHAR. Soil. 



- sometimes, however., in a firm or stony form; 

 under this head may be reckoned lava, tuff stone, and 

 some bog-iron ores. 



The soils themselves may be divided,, according to 

 the agent nature employs in their formation, into 

 marine, fluviatile, and volcanic-^. 



The marine consist of sand, gravel, &c. depo- 

 sited on the sea shores, and in some inland situations 

 to which the sea has still occasional access. 



Thefluviatile are found in vales and lowlands, 

 through which the rivers forming them, at this day 

 take their course. They consist, also, of sand, gra- 

 vel, clay, &c. and, in some particular instances, of 

 calcareous earth, consolidated into a tophus, which 

 frequently involves in its composition moss, bones, 

 and other organic bodies. The deltas of low land 

 at the mouths of large rivers, consisting of sand, 

 mud, &c. sometimes mixed with the trunks of trees 

 and other vegetal matter, are also to be considered 

 as fluviatile formations. 



t To these might be added, perhaps with propriety, the vegetal, 

 or soils originating from a daily accumulation of decayed vegetal 

 matter such are peat and turf soils and the animal, or soils 

 produced by animals which are still employed on their fabrication. 

 Many of the islands in the South Seas exhibit soils of this de- 

 scription, formed by an accumulation of coral rocks. Vide Fors- 

 ter's Voyage, V. 2, p. 146. Phil, Trans. V. 57. p. 29-*. 



