. III. DIST. CHAR. Soil. 167 



and stones belong to the calcareous order. It may 

 be further distinguished, as being 



a. 137. CRETACEOUS ( S. cretaceum) when chalk 

 forms the principal material. 



b. 138. MARMOREAN ( S. marmoreum) in which 

 limestone beds abound. 



c. 139. MARLACEOUS (S. calcareo-margaceum) 

 in which calcareous marl predominates. 



&c. &c. 



B. 140. AN ARGILLACEOUS SOIL ( Solum 

 argillaceum) abounds in beds of clay, or other sub- 

 stances belonging to the argillaceous order. An ar- 

 gillaceous soil may be said to be 



a. 141. SCHISTOSE (S. schistosum) when shale 

 or its varieties f form the beds. 



b. 142. ARENACEO-ARGILLACEOUS (S. arenaceo- 

 argillaceum) when argillaceous sandstones consti- 

 tute the principal strata. 



&c. &c. 



C. 143. A SILICEOUS SOIL (Solum siliceum) 

 in which stones of the siliceous order are most abun- 

 dant. A siliceous soil may be 



a. 144. QUARTZY ( S. quartzosum ) when 

 quartz forms the principal rocks. 



b. 145. ARENACEOUS (S. arenaceum ) in which 

 siliceous sand abounds. 



c. 146. SABULOUS (S. sabulosum) in which gra- 

 vel abounds. 



&c. &c. 



T Slate clay, bituminous shale, alum slate, c. &c. 



