Class Conchifera.  Order, Dimyaria.  Genus Megadesmus.

Valves equal, inequilateral, thick, their edges even; umbones nearly central; hinge sunk, with an antiquated area and one ? or two ? large teeth in each valve; ligament external, large; impressions of the abducter muscles strong, nearly equal, united by the impression of the mantle, at the posterior extremity of which is a small shallow sinus; no lunette.

A genus of heavy shells in some respects resembling Astarte, in others especially in having a striated area within the beaks, Hippopodium, from which it is distinguished by the position of the umbones and the presence of a thick tooth in the hinge.  There appear to be four species, which may be named Megadesmus globosus (Plate 2) M. laevis (figure 1) M. antiquatus (figure 2) and M. cuneatus (figure 3 Plate 3) the cuneatus differs from antiquatus, only in having the shell a little contracted towards the anterior side.

The large shell (Plate 4 figures 1 and 2) is near to Isocardia, but Mr. Sowerby would not venture to say it belongs to that genus.

The Trochus (Plate 4 figures 3 and 4) may be called T. oculus.)

Amongst these remains was also found embedded a very perfect specimen of fossil wood.  I may add, that in the bed of the Glindon Brook, which flows from the left bank of the Hunter, rocks of argillaceous limestone are found in large round boulders, some of which are more than 15 feet in diameter.*

(Footnote.  The fossil vegetation seems to consist chiefly of the Glossopteris brownii (of Brongniart) a fern which occurs in a stratum of ironstone at Newcastle, and in one of the same mineral on the southern coast, also in sandstone in the valley of the Hunter, and abundantly in the shale near the coal wrought at Newcastle.)

November 29.

The whole equipment came up at half-past nine, whereupon I distributed such articles as were necessary to complete the organisation of the party, and the day was passed in making various arrangements for the better regulation of our proceedings, both on encamping and in travelling.  I obtained from Assistant-Surveyor Dixon, then employed in this neighbourhood, some account of Liverpool Plains—­this officer having surveyed the ranges which separate these interior regions from the appropriated lands of the colony.  The heat of this day was exceedingly oppressive, the thermometer having been as high as 100 degrees in the shade, but after a thundershower it fell to 88 degrees.

Men employed on the expedition.

November 30.

At length I had the satisfaction to see my party move forward in exploring order; it consisted of the following persons, namely: 

Alexander Burnett and Robert Whiting, Carpenters. 
William Woods, John Palmer, Thomas Jones and William Worthington,
Sailors. 
James Souter, Medical Assistant. 
Robert Muirhead, Daniel Delaney and James Foreham, Bullock-Drivers. 
Joseph Jones, Groom. 
Stephen Bombelli, Blacksmith. 
Timothy Cussack, Surveyor’s Man. 
Anthony Brown, Servant to me. 
Henry Dawkins, Servant to Mr. White.