550 GEOLOGY OF THE WESTERN COALFIELDS, 



has never been followed by man, so precipitous are its walls, its 

 bed so narrow, and so encumbered by fallen rocks and timber. 

 The Nepean leaves its wide and gently undulating valley for a 

 ravine leading into the heart of the sandstone mountains, there to 

 join the now accessible "Warragamba. The united waters, under 

 the name of Nepean receive the G-rose through a similar funnel 

 (which is almost impassable) and finally, joined by the Colo 

 as aforesaid, strike once more from the open country into 

 the highest part of the range which separates them from the sea, 

 and carve out for their passage the deep and winding chasm 

 known as the Lower Hawkesbury, and extending from Wilberforce 

 to Broken Bay. Of all these facts a rational explanation is 

 required. 



To return to our subject. The Crown Ridge consists of a base 

 of conglomerate, stratified horizontally, though not very definitely 

 the beds not showing out until bleached, as described p. 403. It 

 is variously intercalated with sandstone beds, and is succeeded 

 by (1) fine grained sandstones and shales, with Vei^fehraria, 

 Glossopteris, Fossil Wood, Iron Ore, &c. ; these are overlaid by 

 (2) massive white sandstones and grits, and these by (3) another 

 series of shales, generally of a warm reddish-yellow tint, and full 

 of waterworn fragments and skeletons of Glossoptei^ls and other 

 ferns, PJiyllotheca &c. all lying flat on the lamination faces, while 

 Vertehmria is observed to traverse, as if on the spot where it 

 grew, several inches of shale at various angles. 



These three formations are so well marked and so easily 

 examined at Capertee that I propose to call them — 1. the Lower 

 Capertee Shales. 2. The Capertee G-rits. 3. The Upper 

 Capertee Shales. It would be convenient also to call the under- 

 lying conglomerates and sandstones the Marangaroo Beds, as it 

 is at Marangaroo that they are perhaps best exposed, have 

 certainly been most carefully examined, and have yielded to Mr. 

 Wilkinson's persevering search several specimens of Marine 

 Carboniferous fossils. Above the Upper Capertee Shales the 



