831 



PAET IV. 



UTILIZATION OF COMPONENTS OF THE FOREST SOIL. 



UTILIZATION OF STONE, GRAVEL, ETC. 



IN mountain-forests, the utilization of stone is frequently an 

 important item of forest revenue ; quarrying the better kinds 

 of stone increases in importance with the expansion of towns, 

 the more substantial nature of the buildings erected, and the 

 constantly extending means of communication. Independently 

 of the fact that an absolutely necessary want is thus met, the 

 forest-owner's own pecuniary interest will prevent him from 

 opposing a well-regulated system of quarrying, for the best 

 production of wood will never pay so well as leasing quarries. 



1. Different kinds of Stone. 



The following kinds of stone are utilized : Hewn-stone, 

 which is cut into regular shapes, and for which the fine, com- 

 pact sandstones of the Cambrian, Silurian, New Red Sandstone 

 and Tertiary formations, also trachyte among eruptive rocks, 

 etc., are most in demand. [In Britain, also Bath oolite, 

 Aberdeen granite, etc. T]r.] 



Broken stone used in rubble-masonry, for foundations, etc., 

 for which almost any kind of stone is suitable; or paving 

 stones, for which the hardest material, basalt, phonolith, 

 diorite, fine-grained syenite, etc., are most suitable. Slate for 

 roofing from the Cambrian, Silurian and Jurassic (Stonefield 

 slate) formations, and lignite near Liegnitz and Frankfort, are 

 also valuable. Large quantities of the harder rocks, as well 

 as boulders and gravel, are used for macadamised and paved 

 roads. Calcareous rocks are also of great importance, serving 

 as building-stone or for lime-burning, for which purpose they 

 are the more valuable the less clay they contain ; when mixed 



