No. 3.] MACFARLANE— ON CRYSTALLIKE ROCKS. 



271 



In Slaty Rocks. 



Chiastolitc. 



Chloritoid. 



Damoiuitc. 



Dipyre. 



Falihinitc. 



Ottrclite. 



Para2:onitc. 



Sericitc. 



Staurolitc. 



In Porphyritic rocks. 



Apatite. 



Calcspar. 



Crocidolitc. 



Delcssitc. 



Epidotc. 



Flnorite. 



Gieseckitc 



Halloysitc. 



Iron pyrites. 



Liebenerite. 



Titanite. 



Tourmaline. 



In Impalpalle rocks. 



Hauyuite. 



llmenite. 



Iron. 



Iron pyrites. 



Mngnetic pyrites. 



Nc'pheline. 



Noscan. 



Sapphire. 



Titanite. 



Zircon. 



In Trachytic rocki. 



Apatito. 



Faujasite. 



Haiiynits. 



H',niatite. 



Iron pyrites. 



L'jiicite. 



Mtjlilite. 



Nepheline. 



Nosean. 



Sapphire. 



Titanite. 



Zircon. 



With regard to the origin of these accessorial minerals it may 

 be muintained that by far the greater number of those just men- 

 tioned have been developed during the solidification of the rocks 

 containing; them, and somewhat in advance of the essential con- 

 stituents among which they are found. The evidence of this 

 statement will, howeverj be given in the following chapter. 



VIL — ON THE ORDER IN WHICH THE CONSTITUENTS OP 

 ORIGINAL ROCKS WERE DEVELOPED. 



It cannot be assumed that, in the slow crystallisation of a rock 

 from igneous fusion, its minerals were all developed at one and 

 the s;ime instant. On the contrary, many of them are found 

 under circumstinces which prove that, even after their formation, 

 the mother magna still possessed some degree of plasticity, and 

 m my of the constituents of rocks are so associated and surrounded 

 as fairly to lead to the conclusion that a certain order was main- 

 tained in their gradu:il devclopement. 



The well-known phenomena of fractured crystals iu original 



