264 C. A. SUSSMILCH AND T. W. E. DAVID. 



The sections at Eelah and Martin's Creek were measured 

 by the writer and agree closely as to thickness, but do not 

 agree as to the order of extrusion of the lava flows, par- 

 ticularly with regard to the position of the hypersthene- 

 andesite glass. At Martin's Greek and at Mount Gilmore 

 the series of lava flows starts with a normal hornblende 

 andesite, and is followed by a somewhat more basic hyper- 

 sthene-andesite glass, this in turn being followed by a series 

 of dacites and rhyolites. The names given for the various 

 flows are tentative, and may need revision when chemical 

 analyses are available. Some notes on the igneous rocks 

 of the Kuttung Series are given in Appendix II by Mr. 

 W. R. Browne, B.Sc The thicknesses of the flows in the 

 Mount Gilmore section are not available. 



Excepting at Eelah the general succession of lavas 

 appears to have been from intermediate to acid. The 

 Paterson rhyolite appears much higher in the Kuttung 

 Series and will be referred to later. At Eelah the Martin's 

 Creek horizon is represented by lava-flows and tuft's only, 

 and this was possibly a centre of eruption, but elsewhere 

 interstratifled witli the lava flows and tuffs are some beds 

 of coarse conglomerate and possibly also some mudstones* 



Martin's Creek Andesite. — This is the lowest of the lava 

 flows and owing to its persistent lithological characters 

 throughout the district it forms a useful horizon for map- 

 ping purposes. This flow has a thickness which varies from 

 150 to 300 feet, and is sufficiently resistant to decomposition 

 to give good outcrops. It outcrops on the left bank of the 

 Williams River immediately opposite the township of 

 Clarence Town where it forms the basal flow of the Mount 

 Gilmore volcanic series mapped by Mr. Jaquet; it forms 

 extensive outcrops at Martin's Creek where it is being 

 extensively quarried for railway ballast and road-making 

 purposes; here it forms the base of the Martin's Creek 



