1866.] CLA.RKB AUSIRALIAN CANIfELS. 443 



coal-seams. The Coal-measures thence range to the southward as far 

 as the banks of the Shoalhaven and WoUondilly rivers, the older or 

 Hunter- River beds cropping out from under the upper. About the 

 heads of the Nattai the whole series has been disturbed by the in- 

 trusion of igneous rocks in the Mittagong (or, rather, Merrigang) 

 Range. Immediately upon the older trachytic diorite of the ex- 

 tremity of the range, where it attains an elevation of nearly 2800 

 feet, at Bourell or Gibraltar Gap, but altered by more recent basalt, 

 repose the fragmentary patches of the Hawkesbury rocks, covered by 

 the Wianamatta black shales, in which are a profusion of stems and 

 leaves of Phyllotheca, Cyclopteris, Sphenopteris, and a new genus 

 having the venation of Diplazites, together with the following generic 

 forms of fish : — Myrlolepis, Cleithrolepis, Palceoniscus, and one or two 

 others. 



The shales which contain these fishes are precisely those of the 

 fish-beds of Campbelltown, which also occur at the junction of the 

 Wianamatta and Hawkesbury rocks. 



The insulated hiUs in advance of the Merrigang form the fine 

 Mittagong of the aborigines. One of these summits slopes down to 

 the iron-mine to the south, and, at an elevation of 570 feet above the 

 working coal-seam at its base, forms the top of a precipitous escarp- 

 ment to the north, at the base of which occur four seams of coal, from 

 some of the shales of which I procured Olossopteris and M'Coy's new 

 genus Oangemopteris. In the ravines to the north-west, about three 

 miles from Fitz Roy, the seam was found to have thickened to 38 feet 

 6 1 inches, and appears to have below it a bed of basaltic greenstone 

 (one of the intrusive dykes of the igneous outburst which exerts so 

 extensive an influence for many miles round Mittagong) ; and from 

 250 to 300 feet below all the Coal-measures there occur marine beds 

 with Trochus, Spirifera, &c. 



Above the great seam and at the base of Mittagong is a Cannel- 

 coal. 



The Coal-measures of this neighbourhood are treated of because they 

 belong to the upper measures, and contain peculiar beds, which 

 again present themselves on the Wollondilly, where blocks of brown 

 oil-producing Cannel have been found. Silicates of alumina, and 

 coals full of small cavernous spots (the latter often filled with 

 hydrated oxide of iron in the form of seeds), mark some peculiarities 

 of these deposits ; and these again occur in Burragorang, and occa- 

 sionally further to the west, about the sources of the Cox. 



6. Burragorang. — This is a local name for the part of the "WoUon- 

 dilly valley which occurs between the junctions of the Nattai and the 

 Cox with the former river, and the section of which shows completely 

 that the order of deposits is similar to that of the Illawarra and Nattai. 

 The Upper Marine beds, which occupy the bottom of the section, agree 

 in part with those of Maree, near the junction of the WiUiams and 

 Hunter rivers, passing into the next lower set of beds in that 

 neighbourhood; they support a series of coal-measures which are 

 capped by Hawkesbury rocks, all resting apparently in a nearly 



