114 ME. W. J. CL TOTES ROSS Otf THE [May 1 894, 



minute crystals of, probably, epidote, surrounding large green 

 crystals. The specific gravity of the rock is 3-04. 



The strike of the Silurian strata varies from N.N.W. to N'.N.E., 

 sometimes changing within a short distance. 



4. The Devonian Rocks. 



The passage from Silurian to Devonian beds is not easy to 

 observe near Bathurst, and an actual section showing the junction 

 has not yet been met with by the writer. Nevertheless, there is a 

 distinct change observable, both in the character of the rocks and 

 the nature of the country, when passing from one series of rocks to 

 the other ; and an alteration in the flora may also be noted, the 

 Silurians being richer in species of plants than the Devonians. 



On travelling eastward from Bathurst, one passes over low hills 

 of granite and then reaches the Silurian rocks, which rise into 

 higher hills with a comparatively gentle slope, followed by a fall 

 in the ground to a creek, where one is again at about the level of 

 the city. Once more the ground rises, still with a gentle slope, 

 and the ground is covered with downwash from the hills beyond, 

 so that good exposures of the rocks are not common. Where seen, 

 however, they are still slaty or schistose rocks of the Silurian 

 type. Then the slope becomes much steeper, rising to a height of 

 about 1000 feet, and, on working up the face of the escarpment, one 

 immediately notices that the slates have entirely disappeared, the 

 rocks consisting mostly of massive beds of quartzite and grit, with 

 intrusive sheets of felstone. The summit of the escarpment is in 

 some places a thick bed of conglomerate formed of well-rolled 

 pebbles of, mostly, hardened slate, but mixed with others of more 

 siliceous rocks. The conglomerate does not extend very far if 

 followed along the strike, and elsewhere the highest beds are of 

 grit. The strata dip eastward into the hill at an angle varying 

 from 10° to 30°. By following the course of a creek which runs 

 nearly east and west, some very fair sections may be observed, and 

 the beds are found to be undulating, occasionally dipping west ; the 

 whole appearance of the rocks contrasts markedly with that of the 

 Silurian strata, to which there can be little doubt that they are 

 unconformable. 



The grit-beds, interstratified with the quartzites, are largely 

 made up of the casts of brachiopoda, notably 8pirifer disjunctus and 

 Hhi/neJionella pleurodon, so that they are often called the ' Bra- 

 chiopod Sandstones.' There are, however, a few corals and other 

 fossils as well, including a Lepidodendron, which is of interest, 

 since there has been some doubt as to whether it occurred in these 

 rocks or not. 



Among the fossils enumerated by the late C. S. Wilkinson, 

 F.G.S., from the Devonian beds of Bydal is Lepidodendron noihum, 

 linger. 1 Dr. Eeistmantel, in describing the older fossil plants of the 



1 ' Notes on the Geology of New South Wales,' p. 42. 



