24 PKOF. T. W. E. DAVID & ME. E. F. PITTMATf [Feb. 1 899, 



whereas the cherty claystones, immediately underlying it, dip south 

 7° to 10° east at 23^. The matrix of this rock is dark greenish-grey 

 to greenish-brown, and numerous, pebble-like, rounded to angular 

 fragments are enclosed in it, the fragments ranging up to 9 inches 

 in diameter. Pieces of radiolarian cherty claystone and limestone, 

 mostly angular, and measuring about 7 inches by 5, with thin 

 tuffs, are included in the matrix. In addition to these enclosures, 

 there are numerous pebbles, round or oval, though not necessarily 

 waterworn. Some of these are porphyritic andesites, such as the 

 rock described in micro-slide No. 621 (p. 36), and one of them 

 is distinctly amygdaloidal. The whole rock has very much the 

 appearance of a volcanic agglomerate. Its matrix is very like 

 that of the 22-yards tuff at Tamworth Common, but contains 

 rather more angite, and in addition aggregates of calcite. A 

 chemical analysis of this rock is tabulated on p. 32. Probably this 

 agglomerate-like mass at Cleary's Hill is part of the mass seen in 

 the hiU some 500 yards farther east, and it is closely related to, if 

 not absolutely identical with, the similar rock capping the spur more 

 than I mile north of Cleary's Hill. 



At the easterly outcrop, there can be little doubt, in the opinion of 

 one of us (T. W. E. David), that the small pebbles are of waterworn 

 origin. Possibly they may represent the basal conglomerates of 

 a newer formation, such as the Carboniferous. Whether the large 

 blocks of quartz-felsite and the smaller fragments of porphyritic 

 andesite owe their rounded surface to corrosion or erosion is doubtful. 

 Equally spherical blocks, owing their roundness to corrosion in an 

 eruptive magma, have been observed at the Pennant Hills Basalt 

 Quarry, near Parramatta.^ Whatever may have been their mode of 

 origin, we do not consider the pebbles and rounded blocks to belong 

 to the radiolarian series. 



Prom the bed just described up to the outcrop of the massive lime- 

 stone seen in Tamworth Temporary Common the strata are still 

 cherty radiolarian shales, with one bed of lenticular radiolarian 

 hmestone marked D in PI. Ill, and another marked C, in the 

 same plate. There are besides a great many beds of tuff, one of 

 the most conspicuous of which is shown at T (a) in PI. III. The 

 thickness of beds, including tuffs, from D to C is about 1430 feet ; 

 the radiolarian limestone C is about 2 feet thick. The thickness 

 of strata from C to the top bed seen east of the great fault, and 

 adjoining the coral-limestone, is about 1450 feet. 



A third horizon for Lepiclodendron australe occurs in this division 

 of the beds : several well-preserved specimens being discovered by 

 us in Porter's Gully, a locality for these fossils which was pointed 

 out to us by Mr. Donald A. Porter, of Tamworth. At the quarries, 

 west of the coral-limestone near B (PI. Ill), radiolaria occur in 

 abundance in soft clay- shales, in which they show clearly to the 

 unaided eye as small round grains, and with a pocket-lens the 

 reticulate structure of the tests can be distinctly seen on freshly- 

 broken or on weathered surfaces. These beds are minutely lami- 

 ^ See Journ. Eoy. Soc. N.S.W. vol. xxvii (1893) pp. 401-406. 



