Page:A sketch of the physical structure of Australia.djvu/53

41 across the main chain, hereabouts, through Yass Plains and by Lake George to the Shoalhaven River, as mentioned before (p. 18), the granite on which they repose, being, however, here and there exhibited at the surface.

Returning to Mount Byng and following Sir Thomas back to the eastward, we read of hills of vesicular lava, till we approach Mount Cole, and a north and south range called the Pyrenees, which consists entirely of granite, as does the country around Weelbong sixty miles to the northward of Mount Cole. East of Mount Cole, vesicular lava and basalt again occur up to the foot of the Grampians. The Grampians are described as a bold range of hills, 4000 feet in height, running north and south for about fifty miles, and composed from top to bottom of thick bedded ferruginous sandstone. Trap appears to the N.E. of them, while to the west in the upper part of the Glenelg River much granite was seen—and near the Wando River, gneiss, granular feldspar, and fine grained sandstone.

All the lower part of the Glenelg River, Sir Thomas describes as traversing a country evidently composed of the tertiary formation. He speaks of "a thin stratum of shelly limestone bearing some resemblance to some of the oolitic limestones of England," with "irregular concretions of ironstone containing grains of quartz, some glazed externally by a thin coating of hœmatite." Near Fort O'Hare, he describes "limestone rock with fossil oyster