!>' AUGURAL ADDRESS. 
9 
belt along the coast from Point Danger to Gladstone. Further north 
there are extensive patches of Desert Sandstone belonging to this 
period, though the designation seems to have been applied to two 
distinct beds of sandstone, one belonging to the close of the Mesozoic, 
and the other to the last part of the Cretaceous. 
GREAT DEPRESSION AND ERUPTIONS. 
Ultimately the dry land was reduced to the eastern ranges, from 
Cape Howe northerly to latitude 15 degrees; the eastern side nearly 
the same as the present coast line, and extending from 100 to 300 
miles westerly, while the Mount Lofty Range in South Australia 
existed as an island. This great depression was accompanied by dis- 
locations of strata, and also by the eruption of porphyritic masses, the 
age of these eruptions being easily determined as they rest on the 
Ipswich coal strata. At Mount Flinders the base of the mountain 
consists of coal shales with abundant impressions of Pecopteris, while 
there is a more instructive instance near Teviot Brook, where in a deep 
ravine there is a dyke of porphyry cutting through a bed of car- 
bonaceous shale, with Pecopteris and the silicided stems of pine trees 
embedded. The dyke itself is dark-coloured and highly crystalline, 
but where it spreads out into a fiat sheet on the top of the hill, it 
assumes the same appearance as the light-coloured porphyry of Bris- 
bane. This porphyry forms the Glasshouse Mountains, which are so 
conspicuous from the entrance of Mo ret on Bay, and also Mounts 
Warning, Leslie, Maroon, and Barney. 
The central and western parts of the continent were almost entirely 
submerged in the ocean, but not to any great depth, as the higher granite 
peaks of the north-west do not show traces of submergence, though 
the sedimentary deposits approach closely to their bases. The 
Stirling and Mount Barren Ranges on the south coast were only 
partially covered, as there is an ancient sea beach on the south side 
of middle Mount Barren, about 300 feet above the present sea level. 
The interior tableland, though now of greater altitude than Mount 
Barren, was submerged, as evidenced by the extension over the whole 
of the rest of \V est x\ustralia of soft sandstones and clay-stones, in 
which salt and gypsum are of common occurrence. On the northern 
coast the submergence was greater, as the sandstones and shales have a 
thickness of more than a thousand feet. 
THE CRETACEOUS DEPOSITS. 
One characteristic of the latter part of the Cretaceous deposits is 
that in the lower part they consist chiefly of white, blue, and pale red 
shales, which readily disintegrate, while the upper portion consists of 
variegated sandstones of a harder character, with a comparatively thin 
covering of ferruginous concretionary pebbles or nodules, often with 
a nucleus of organic origin. On the west coast (latitude 29 degrees), 
on Moresby s hlat-toj^ped Range, these features are well developed, 
