Yol. 55.] PALEOZOIC EADIOLAKIAN EOCKS IN IfEW SOUTH WALES. 23 



surrounded by the tuff. Unweathered impressions of Lepidodendron 

 australe retain some carbon, referable obviously to the material of 

 the original plant. These casts are about 28 mm. wide, 150 to 

 300 mm. long, and 3 to 25 mm. thick. A score or so were observed 

 by us, as well as a cast of a fluted stem, perhaps a calamite, 150 mm. 

 long and 25 mm. wide. ' Several of these specimens were observed 

 in situ in the undisturbed tuff, at its outcrop on the precipitous 

 slope of the hill. 



The sedimentary claystones and the tuffs appear to be so inti- 

 mately mingled together at this spot that it is difficult in places to 

 define their original boundaries without the aid of thin micro-slides, 

 a number of which have been prepared. A feature which we 

 would specially desire to emphasize is the occurrence of the radio- 

 larian limestone E (see PL III) only 6 inches above the stratum 

 which contains so many examples of L. australe^ and moreover, in 

 some examples from this horizon, chalcedonic casts of radiolaria 

 abound in the same rock as that which contains L. australe. 



The thin tuff-beds and intervening cherts with which the L, aus- 

 trale is associated at the radiolarian limestone-bed E are about 

 7 feet thick. Between E and the next limestone-bed, D, there is 

 a thickness of about 1960 feet of the usual claystones, cherts, and 

 tuffs, with probably a few lenticular bands of radiolarian limestone, 

 which we in our traverses failed to strike. The radiolaria in some 

 of these cherts are of comparatively large size, up to 0'36 mm. in 

 diameter, as shown in micro-slides I^os. 274 & 628. 



An interesting feature in this part of the section is the occur- 

 rence of fine conglomerates, with which is associated a curious dark 

 greenish-brown tuff containing rounded blocks of eruptive rocks 

 from a few inches up to over a foot in diameter. 



With regard to its occurrence in the field, this rock appears to 

 occupy the uppermost position in the group of Palaeozoic rocks near 

 Tamworth. It occurs in considerable thickness, capping a hill which 

 separates the mouth of Long Gully from that running through 

 Cleary's selection, about 1 mile north-east of Tamworth Railway- 

 station. A good section is also exposed in the ridge about ^ mile 

 east of the last-mentioned locality, and the same rock is visible as a 

 thin capping on the range about ^ mile north. In the second locality 

 there is evidence suggesting that what at first sight appear to be 

 bedding-planes are really examples of well-developed and regular 

 jointing, for crossing these lines nearly at right angles are some- 

 what irregular but distinct pebble-beds in which the pebbles vary 

 in diameter from 6 to 25 mm. The joint-planes dip 40° south- 

 south-east, while the pebble-bands dip west 30° south to south-west 

 at about 22°. Included in the matrix are the blocks of hornblendic 

 quartz-felsite, over a foot in diameter, already mentioned. The 

 pebble-beds cannot be broken or separated from the overlying and 

 underlying rocks by any defined planes of deposition and, as above 

 stated, their course is not absolutely regular. 



At Cleary's Hill, more than | mile west of the spot just described, 

 a similar rock of agglomeratic appearance dips south 20° west at 22°, 



