DIALLAGE 



seems also to pass in a gradual manner into ser- 

 pentine ; or, at least, the boundaries of the two 

 are not always to be defined. For this reason a 

 mixture of diallage and serpentine has been in- 

 cluded among the varieties in the Synopsis. It 

 will probably be found to present many other 

 modifications when it shall become better known ; 

 but, in the mean time, I have introduced into the 

 catalogue, among the more legitimate varieties, 

 all those mixtures in which diallage occupies a 

 conspicuous place ; trusting to future observa- 

 tions , for the correction of this still imperfect 

 account. 



SYNOPSIS OF DIALLAGE ROCK. 



FIRST DIVISION. 



Simple : of diallage alone. 



A. A confused mixture of crystals of diaMage. 



The aspect of this simple rock varied mate- 

 rially according to the magnitude of the crystals ; 

 and it appears rather to form veins or concretfonfc 



