484 ON THE CONNECTION OF GEOLOGY 



section is made of them, they exhibit a series of parallel 

 curved lines. 



2. River Soil, or the soil found in the beds and banks 

 of rivers, and which is produced by the continual propel- 

 ling power of large rivers. To this class belong two 

 different kinds ; 1st, Soil containing pebbles of various 

 sizes, produced by the power of torrents in the vicinity 

 of mountains ; and, 2d, Earth or mud, deposited in the 

 beds of rivers, in places at a distance from mountains. 

 A peculiarity of river soil in general is, that it is much 

 extended in length, while its breadth is comparatively 

 but small. The different layers have neither so much 

 irregularity as in the preceding kind, nor are they so 

 precise in arrangement as in the following. 



3. Lake Soil, deposited at the bottom of still water. 

 To this class is to be referred the soil in the bottoms of 

 valleys, which had formerly been lakes, either separate 

 or connected with rivers. The horizontal dimensions of 

 this kind of soil are often more or less equal. Some- 

 times, indeed, the length is greater than the breadth ; not, 

 however, in the same degree as in soil deposited in the 

 bed of rivers. The surface is usually plane, and the dif- 

 ferent strata alternate in a parallel manner. 



4. Marine Soil, that is to say, the mud of the an- 

 cient ocean. It is the greatest of all in its extent, both 

 in a horizontal and a vertical direction. Its surface is 

 more or less undulated, very seldom even. Its masses 

 are .both very thick and very uniform in composition. 

 Different and alternating strata, however, do occur, 

 whose forms and dimensions are usually more or less 

 regular, and which are not unfrequently undulated. 



Soil, after being formed, is acted upon by natural 



