§rbt0,l §wiltint0 Stones. 



By PEOF. C. LLOYD MORGAN", 



Univ. Coll., Bristol. 



" /COMMENCING- witli what arc commonly called build- 

 ^^ inf materials," writes Prof. Anstod in his Cantor 

 Lectures (1865), " we may regard them as of three classes — 

 granites, sandstones, and limestones. Praotioally there is 

 another division of the whole number into two classes ; 

 namely, those which can only be worked by the pick or 

 by wedges, and those which can bo worked by the mallet 

 and chisel. The latter are called freestones, and include 

 marbles all limestones, and stratified sandstones. The 

 former include granites, quartz rocks, and indurated schists, 

 conglomerates or pudding-stones, in which quartz predomi- 

 nates and some agglomerated sandstones that cannot be 

 fitly called pudding-stones. Of these some are rarely used 

 on a large scale, except in the immediate vicinity of the 

 rocks whence they are derived, and thus, practically, the 

 number of those which wo have to consider is reduced 

 within reasonable limits." 



In such a course of lectures, Prof. Ansted could afford 

 to no"-lect such stones as are " rarely used on a large scale, 

 except in the immediate vicinity of the rocks whence they 



95 a 



