394 W. R. BROWNE AND A. B. WALKOM. 



a 



The country between the Drake's Hill volcanics and 

 Maluna " is composed principally of Lower Marine 

 sediments — conglomerate, sandstone and foraminiferal 

 limestone. A belt of basaltic or andesitic lava can be 

 imperfectly traced by means of the resulting soil and by a 

 few obscure and decomposed outcrops, but this has not 

 been accurately mapped, as the boundaries are impossible 

 of delimitation. 



North of the Drake's Hill area, in the Parish of Rothbury, 

 is a small low conical hill composed of basalt, with a few 

 short dykes radiating from it. The relations of this outcrop 

 are much obscured by recent alluvium, but it is in all 

 probability contemporaneous in the Lower Marine. It is 

 surrounded by Lower Marine sandstones which a short 

 distance away are distinctly dipping towards the outcrop. 



Order of Succession of the Lavas. 

 As a result of our investigations we are inclined to 

 advance the following order of succession for the rocks of 

 the district : — 

 Carboniferous : 



i. Rhyolite and rhyolite tuffs, 

 ii. Trachyte, beginning with leucocratic, and followed 



by melanocratic. 

 iii. Agglomerate, trachy-andesite and andesite. 

 iv. Dolerite and olivine basalt necks, and basalt flows, 

 v. Dacite and (?) dykes of trachyte. 



Permo-Oarboniferous : 

 vi. Basalt. 



The positions of the rocks under iv, and of the trachyte 

 dykes are of course not certain, but there is little doubt 

 that the general character of the succession is correct. 

 There seem to have been several eruptions of rhyolite, both 

 as quiet flows and as explosive outbursts. The trachyte 



