﻿18 THE J)YKE AT CROOEDENE (NORTHUMBERLAND). [Feb. I9IO, 



EXPLANATION OF PLATES I & II. 



Bocks of the Crookdene Dyke. 



Plate I. 



Fig. 1. Junction between the basalt and the shattered portion of the felspar 

 aggregate. The nicols are crossed, and the zoning of particles em- 

 bedded in the basalt is shown (A), as also the absence of zoning in 

 felspars embedded in felspar-dust (B). Magnified 15 diameters. 

 2. Specimen showing elementary forms of crystallization (ef. E. B. Bailey, 

 Trans. Geol. Soc. Edin. vol. viii, 1904, p. 303). Branches of ele- 

 mentary augite (A) curve up on one side and down on the other of a 

 felspar lath (F). The augite has been entirely replaced by calcite. 

 Crossed nicols. Magnified 196 diameters. 



[On the Plate itself the statements of magnification have been accidentally 

 interverted, as between figs. 1 and 2.] 



Plate IT. 



Fig. 1. Specimen showing curved angites (A) and felspar (F). Crossed nicols. 

 Magnified 80 diameters. 

 2. Felspar aggregate shattered and slightly faulted. Magnified 15 

 diameters. 





