BY] A. B. WALKOM. 153 



Iii portion 91, Parish of Stanhope, there is a development of 

 basalt and breccia in this series. This may represent a centre of 

 volcanic activity, which was responsible for the tuffaeeous nature 

 of the sandstones next to be described. 



Following the mudstones, there is a thickness of about 120 feet 

 of rather coarse tuffaceous sandstone. Good outcrops occur, the 

 best being those in portions 8, 96, 78, 76, and 74, Parish of Stan- 

 hope. It is thus seen that this sandstone occurs continuously on 

 the western and south-eastern sides of the basin, but has not been 

 observed to outcrop on the northern side. This absence on the 

 northern side is due to the presence of the Webber's Creek fault. 

 The sandstone contains numerous marine fossils, there being, in 

 places, regular banks of such thick-shelled molluscs as Eurydesma 

 cor data, Platyscliisma, etc., indicating turbulent, shallow-water 

 conditions during the deposition of the beds. The fossils present 

 in this sandstone include — 



Spirifer duodecimcostata. Pachydomus. 



S, tasmaniensis. Scaldia(X). 



Martiniopsis subradiata. Platyschisma octdus. 



Aviculopecten mitchelli. Mourlonia. 



A. tenuicollis. Ptycomphalina, 



Eurydesma cordata. Hyolithes lanceolatus. 



In appearance, this sandstone is sometimes very similar to that of 

 Harper's Hill, and the similarity is increased by the occasional 

 presence of andesitic boulders, with numerous amygdules of second- 

 ary silica, calcite, etc. 



The remainder of the Lower Marine Series consists of about 

 330 feet of mudstones, sandstones, and conglomerates, in which 

 fossils appear to be very scarce. At Eui Creek and Billy Brook, 

 these are somewhat hardened and jointed, probably as a result of 

 their proximity to the Webber's Creek fault. 



(ii.) Greta Coal-Measures. — Above the Lower Marine Series, the 

 Greta Coal-Measures are developed. They consist mostly of the 

 sandstones and conglomerates typical of these measures, and there 

 are also developed some beds of a brownish shale, as well as at least 

 one coal-seam. The outcrop can be traced continuously round its 



