334 PROCEEDINGS OF SECTION C. 



published by the Mines Department, for information on the 

 geology of that part of the country. 



In the section the Carboniferous rocks of Lithgow and the 

 surrounding district are shown to consist of two divisions — 

 the upper coal-bearing series, probably the same age as the 

 Newcastle beds, and a lower division, including the so-called 

 Upper Marine and Lower Coal Measures. They rest partly 

 on granite and partly on the underlying Devonian beds, to 

 the latter of which they are cpjite unconformable, the dip of 

 the Carboniferous being given as about 5°, while that of the 

 Devonian is given as about 30°. The Devonians are folded 

 on a large scale, and the section shows a fine synclinal 

 between Mount Walker and Rydal. The total thickness of 

 the beds is stated to be 10,000 feet by measurement. The 

 section is continued to Mount Lambie, whence to the locality 

 with which we are concerned in this paper there is a gap of 

 fully sixteen miles in a straight line, concerning which I can 

 find nothing published. At a few places along the line I 

 have been able to examine the rocks, but do not find any 

 marked difference from the Devonian beds described by Mr. 

 Wilkinson except in the neighbourhood of mineral veins, 

 while the fossils in the gritty beds already mentioned are the 

 same as soine of those quoted from the Devonian at Kydal 

 as having been named by Professor De Koninck. It appears 

 therefore likely that the Devonian beds extend from east of 

 Rydal on the Western Railway Line to within ten or twelve 

 miles of Bathurst. They appear generally to terminate in a 

 bold escarpment. At the place where the Lepidodendron 

 was found this is especially well marked. It is a narrow 

 valley, almost a gorge, down which a small stream runs. 

 The sides are very steep, and the beds which form them — 

 grits, quartzites, &c. — dip eastward. There has been a good 

 deal of slipping in the rocks, and the dip appears to vary in 

 amount, but is nowhere greater than 30° so far as I have 

 been able to determine it. On proceeding up the stream 

 from where it joins the Wimburndale Creek for a mile or 

 two, one reaches a small waterfall formed by a ledge of 

 quartzite. Above this the valley becomes steeper, but there 

 is no important change in the rocks until a double series of 

 falls, forming the head of the A^alley, is reached. The upper 

 and largest of the three is due to a thick and very massive 

 conglomerate, which forms the summit of the escarpment. 

 At the side of the valley near the upper fall there is a 

 distinct fold, and the beds for a short distance dip west. I 



