BY W. N. BENSON. 503 



the Liverpool Plains, and the hills between the Peel River and 

 Goonoo Goonoo. Their thickness is doubtless very great, but has 

 not been proved, as nowhere have the top and bottom been seen 

 in one section, nor can due allowance be made for strike-faulting, 

 owing to the absence of horizons of reference. A thickness of 

 about 8,000 feet is apparently developed between the fault east of 

 Burindi and the marine beds to the west, and an apparent thick- 

 ness of about 13,000 feet occurs between the Peel River and 

 Squaretop by Nundle. 



(d) The Burindi Series lies conformably above these mudstones, 

 and it has not yet been possible to draw a sharp distinction between 

 them. They consist of a fine, dark grey, fissile mudstone, with 

 bands of tuff of an andesite nature, and occasionally a rather 

 coarsely grained, tuffaceous breccia. Here and there are thin 

 bands of limestone, composed almost entirely of crinoid-ossicles, 

 and other beds largely oolitic. The formations have a very wide 

 extent. They are found in the north, on Slaughterhouse Creek, 

 near Gravesend, and thence, traced southwards, occur to the east 

 of the Rocky Creek Series, all along its development. Just beyond 

 the limits of the area studied, it is very well developd at Somer- 

 ton, where a considerable thickness of highly fossiliferous lime- 

 stone was found by Mr. Stonier(6). From information gathered, 

 it would appear to cover a considerable area running north-west 

 of here, appearing from beneath the syncline of Rocky Creek con- 

 glomerate that lies west of Burindi. Fossils have been found at 

 Rangira, which probably belong to this Series, but they have not 

 yet come under scientific notice. Further south, there is an exten- 

 sion parallel to the Rocky Creek conglomerates. Marine fossils 

 have been collected near Goonoo Goonoo and Gundy, and are de- 

 veloped in great amount in the Paterson-Clarencetown area, north 

 of Newcastle, as studied by Messrs. J. B. Jaquet and L. F. Harper 

 (12). There are also other areas of development to be considered. 

 Along the western margin of the serpentine, stretching from the 

 head of Hall's Creek to the Namoi River, is a line of similar mud- 

 stones and tuffs, which contain Carboniferous fossils. The 

 southernmost occurrence is near the Namoi River, and consists of 



