Ch. 34] 



1 (Continued) 



PROPERTIES OF ROCK TYPES 



641 



2 Scale applicable to all other properties: I, excellent; II, good; III, adequate or fair; IV, poor, or usable only in emer- 

 ency; V, inadequate, unsuitable, or absent. 



3 The rock mantle becomes thin along the slope and disappears altogether at scarps. 



4 When wet, best worked with hoe or drainage spade. 



