720 GREAT SERPENTINE BELT OF NEW SOUTH WALES, Hi., 



occurring adjacent to the serpentine, west of Gulf Creek. It should 

 possibly be classed with the Rocky Creek beds, for it consists of a 

 mass of rhyolite and trachyte-fragments of several types, with 

 quartz-grains in a finely divided quartz and felspar ground-mass 

 [N.T., 483]. 



The limestones are of several types. Where fossiferous, they 

 are remarkable for being composed almost entirely of crinoid- 

 ossicles, and are sometimes quite pure, at other times very ferru- 

 ginous. Oolitic limestones occur at several localities. That near 

 the junction of the Horton River with Rocky Creek, was briefly 

 described by Mr. Etheridge (see Stonier's Map, 6d). Oolitic lime- 

 stones occur also near Mr. Hamilton's house on Oakey Creek, five 

 miles south of Warialda. That near the serpentine, half a mile 

 east of the house, consists of normal, zoned, radially fibrous oolites, 

 about 3 mm., in diameter, in a tuffaceous matrix of quartz-grain s, 

 felspars, chlorite, and fragments of a basaltic rock. Crinoid- 

 ossicles are also present abundantly. 



Some limestones of this series, as, for instance, a small band by 

 the HalPs Creek Falls [M.B., 284] are very impure, full of pebbles, 

 weathering with a brown crust, and are indistinguishable from the 

 Devonian limestone occurring near Cuerindi [M.B., 85, p. 711]. 

 Nothing especially noteworthy, petrologically, is to be remarked in 

 the very fossilferous Lithostrotion limestone near here. It is fairly 

 pure and crystalline. 



(6) The Rocky Creek Series consists of volcanic flows, tuffs, con- 

 glomerates, grits, sandstones, and cherty rocks. The clastic rocks 

 all contain fragments of the interbedded lavas, and of other 

 igneous rocks also. Even the finest-grained cherty rocks contain 

 fragments of granite. There are not, however, as far as has 

 been noted, any red jaspers or other rocks comparable with the 

 rocks of the Eastern series, to be found as inclusions in the Rocky 

 Creek beds. The suspicion that arose, in one or two cases, has 

 been dispelled on microscopical examination. The following are 

 micropetrological notes on a few slides: — 



Cherts: [M.B., 16]. Interbedded in the conglomerates on Rocky 

 Creek. Composed of very finely grained, angular quartz and fel- 



