niscovite and tourmaline, the latter 

 both massive and columnar. 



Di/ke Rocks.— Only two typical dyke-masses were met 

 with, but from the abundance of quartz veins through tlie 

 slates, clay, ironstones, etc., it seems likely that many are 

 hidden by the depth of alluvial which hides true outcrops 

 all over the island. Of these dykes, one at the mouth of 

 the Ettrick River is composed of a coarse grained dolerite 

 with porphyritic felspars. Its augite is almost, completely 

 ura lit ized, and its abundant ilmenite is largely altered to 

 leucoxene. The dyke is about twenty feet broad and runs 

 in a direction parallel to the strike of the slates, but there 

 is evidence to show that it is not a sill. 



The second intrusive rock is met with on the road to the 

 Sea Elephant Gold Mine, a spot about four miles from 

 Currie Harbour. It is in thick scruh and was found entirely 

 by accident, but its outcrop is very well defined for about 

 fifty yards as a bank of sandy soil lightly covering the rock. 

 The surrounding country is widely traversed by veins of 

 smoky quartz and the dyke itself is fringed by the same. 

 The rock itself is a basalt containing abundant augite, 

 ophitic to the subordinate felspar and accessory minerals. 



Of other igneous rocks on the island two may be men- 

 tioned as being reported, but they were not visited by the 

 writer. Of these the gabbro reported from Bold Head 

 seems very probably correct, judging from a chip shown to 

 the writer. The basalt shown on the map south of the 

 Praser River is on slender evidence only, but is interesting 

 in connection with the discovery of a basic tuff at the Oity 

 of Melbourne Bay. 



The field relationships of this tuff were unfortunately 

 hidden by sand, but inclusions of the palaeozoic rocks are 

 found in it. It is a hard reddish rock, and under the micro- 

 scope is not very satisfactory, as it is very decomposed. 



