ACTINOLITE SCHIST. 173 



experienced ; from the facility with which it is squared 

 by the hammer alone, as well as from its strength and 

 durability. It is also among the best of paving stones. 



Actinolite Schist. 



While mineralogists shall distinguish actinolite from 

 hornblende, this rock must be separated from horn- 

 blende schist; and I am thence bound to notice it, though 

 its geological history is but the same. Substituting acti- 

 nolite for hornblende, the definition is given; and if, 

 when simple, it varies according to the magnitude, form, 

 and interlacement, of the crystals, so, when compounded, 

 the analogy is equally perfect, though varieties also 

 occur, containing mica, talc, chlorite, and hornblende. 



The Geological information respecting it is so tri- 

 fling that I can only quote Saussure, though his re- 

 marks afford nothing for the present purpose. In my 

 own observations, it becomes a substitute for horn- 

 blende schist, alternating with gneiss, while both fre- 

 quently occur together. In general, it is in small 

 quantity; and thus it is found dispersedly in many 

 * parts of Scotland, and in the Shetland islands. In 

 one instance it forms a distinct and considerable pro- 

 longed bed, well known in Glen Elg, where it occupies 

 the summit of a hill, re-appearing in Eilan Oransa on 

 the shore of Sky. It is likely that it forms similarly 

 extensive beds in the Swiss Alps. In one instance 

 only, I have found it forming laminae in primary lime- 

 stone, in Atholl; and it occasionally occurs in mica- 

 ceous schist, where this is intermixed with chlorite and 

 hornblende schists. It accompanies serpentine, in Shet- 

 land, under an association leading to no conclusions; 

 and I have recently described its peculiar connexion 

 with Chlorite schist. 'That it furnishes specimens to 

 collectors, is all that I can further say repecting its 

 natural history. 



