CHAPTER XL 

 THE CAPE GRAY METAMORPHOSED DYKE SERIES. 



In each exposure on the Cape Gray Promontory basic dykes are found traversing 

 the garnet gneisses. Photographs were obtained from the localities visited by the 

 sledging party from the mainland, and these show the obvious dyke characters (Plate 

 XXVI., fig. 4 ; Plate XXVII., figs. 1, 2, 4). 



Each locality will be dealt with separately, as each possesses different metamorphic 



features. 



Cape Gray. 



At Cape Gray a perfect network of dykes is visible on the bare rock floor. A 

 diagrammatic sketch of this network is given in Fig. 13. The dykes branched and 

 junctioned frequently and small tongues could be seen running from the dyke channel 

 out into the gneiss (Plate XXVII., fig. 2). In places they enclose large fragments of 

 gneiss. So perfectly preserved is the network, we immediately assumed that the dyke 

 series would be much younger than the development of the gneiss. Examination, 



Fig. 13. 



DIAGRAMMATIC SKETCH OF THE RELATION OP THE GARNET CORDIERITE 

 GNEISS TO THE PLAGIOCLASE PYROXENE GNEISS AT THE WEST END 



or CAPE GRAY. 

 The shaded area represents the garnet cordierite gneiss. 



