BY W. N. BENSON^ W. S. DUN, AND W. B. BROWNE. 



299 



tliese again by the Main Felspathic Grit which extends beyond the point where 

 Anstey's Creek enters the main stream. The grit contains intercalated bauds of 

 conglomerate. 



(b) The Main Felspathic Grit which thus immediately overlies the lower 

 glacial beds is the most uniform portion of the Kuttung Series in this district. 

 It is a strongly cemented grit chiefly composed of fragmental grains of orthoclase 

 and quartz with a little albite et cetera. Here and there it contains interstratified 

 pebble-bandSj passing into deiinite layers of conglomerate, and also occasionally 

 thin bands of mudstone. Its great resistance to erosion is seen from the per- 

 sistency with which it forms the highest ridges throughout the whole of the district. 

 It probably forms "Rocky Peak," between Quipolly and Werrie's Creeks, and then 

 north of it rises to form Soma, and the point immediately north of it (both 

 of which are higher than Duri Peak) ; it also forms the ridges east of Rocky 

 Creek, and those lying just west of the watershed between Currabubula and Turi 

 Creek. No fossils Lave yet been found in this formation, which is approximately 

 a thousand feet thick. It evidently resulted from prolonged explosive eruptions 

 which culminated in the production of a little rhyolitic tuff, possibly in some parts 

 rhyolitic flow-breccia, about fifty feet thick. This last has been traced down 

 the eastern side of Rocky Creek, and along- the western foothills of the ridges 

 north of Currabubula. 



The Upper Portion uf the Kuttung Series. 



The beds following this are again more or less glacial in character. North 

 of Currabubula Creek, a little basic tuff and a flow of basalt only a yard wide 

 intervene between the rhyolitic tuff and the tillite, but these are absent from the 

 development in Rocky Creek where also some faulting appears to have obscured 

 the succession. The tillite has the same general characters as that in the Lower 

 glacial beds, and contains striated pebbles of quartzite {see footnote on p. 297) 

 among many more or less rounded boulders of granite, porphyi-y, and aplite. 

 It becomes more conglomeratic in character in its higher portions, and is inter- 

 stratified with a large amount of felspathic tuff. About fifteen hundred feet above 

 the top of the Main Felspathic Grit there is a narrow zone of fine-grained, white 

 felspathic tuffs, which may be traced up the face of and the spur to the south of 

 the hill immediately to the south-east of Currabubula. Traces of Hhacopteris 

 have been observed in this, and associated with it are contorted banded tuffs some- 

 what resembling "varve" rock. Altogether these are rather more than fifty feet 

 thick. Two miles from Currabubula Station, in portion 274, where the western 

 branch of Rocky Creek crosses what is probably this horizon, coarse tillite is seen 

 containing several narrow layers of "varve" rock up to a foot in width. 



TJie Kuttiinri Rocks West of Werris Creek. 



The Kuttung rocks, which make the western limb of the syncline, form the 

 hills to the north and south of Werris Creek Gap. They have not yet been in- 

 vestigated in detail, but appear to be similar to the upper portion of the Kuttung 

 Series near Currabubula. Intercalated in these is a mass of andesite thirty feet 

 thick, which closelv resembles the rock termed the Martin's Creek andesite in the 

 Paterson District, which there has been shown to be a flow. Immediately to the 

 west of these hills extend the Liverpool Plains which, near the Werris Creek Gap, 

 are covered by black soil, probably derived from the Werrie basalts. It is 

 possible that the western face of these hills is parallel to a line of strike-fault 



