160 . HI. DIST. CHAR. Soil. 



They are always stratified-^. They abound in 

 extraneous fossils. 



Obs. The formation of these soils is evidently 

 posterior to that of the ancient secondary, as they 

 constitute, in most instances,, the lower hille and 

 plains,, under which strata from the ancient secon- 

 dary mountains are always observed to dip. 



The rocks belonging* to the soils of this order, 

 are some limestones, particularly the porous kinds, 

 chalk, basalt^ sandstones., puddingstone, black coal, 

 Tnarl, marlite, shales, argillaceous ironstone, gyp- 

 sum, and rock-salt ff. They may be divided into 

 marigenous, semimarigenous, and alluvial^ f f. 



The marigenous contain marine rcliquia only 

 as the bones, &c. of sea fish, shells, echini, &c. 

 They consist, for the most part, of the open-grained 



ancient secondary rocks 1 In some few instances, at least, this 

 appears to be the case, as coal, which in general belongs to the less 

 ancient secondary soils, has been found immediately on granite. 

 v. Kirw. G. Ess. p. 346\ 



f Hence, in the Wernerian school, the rocks of these soils 

 are distinguished by the term floetz or stratified. 



ft Some of these substances, particularly marl, gypsum, and 

 rock-salt, are perhaps more common to soils of later formation. 



ttt They have also been distinguished as original and deriva- 

 tive rocks : such are generally considered to be original as have 

 not, in appearance, been formed from the disintegrated parts of 

 other rocks the derivative are those which evidently owe their 

 origin to the decomposition of more ancient strata. Many rocks, 

 however, seemingly original, may, in reality, be derivative. 



