16 
Along the coast, between the month of the Gascoyne, around North-West 
Cape and Exmouth Gulf, and as far as the mouth of the Ashburton River, there 
are low limestone cliffs facing the sea, whilst inland, on the top of these, for i 
about 100 miles, is a sandy table-land, probably of Mesozoic age. 
Between the Minilya, the Henry, the Lyons, and Ashburton Rivers is a high 
crystalline limestone table-land, of Palaeozoic age (Devonian P), with here and there 
bold ranges, as the Barlee Range, through which the rivers have cut large valleys 
and deep gorges in these almost horizontally bedded rocks. 
The Minilya and Lyndon rivers take their rise in the limestone country 
a little to the Westward of Mt. Thomson, which is situated at the great bend of 
the Lyons River. They are about 100 miles in length, flowing over the Car¬ 
boniferous, Mesozoic, and Tertiary rocks, and discharging themselves into a large 
swamp, which is separated from the sea by a low coastal sandstone ridge. This 
swamp overflows at the North of the mouth of the Gascoyne River, also about 100 
miles further North, a little to the Northward of Cape Farquhar. 
The Gascoyne River, for the first 20 miles from the coast, flows over an 
alluvial or estuary deposit of fine loam and brick earth, and for the next SO miles 
in an Easterly direction through a sandy table-land of Tertiary age. For the next 
20 miles it passes through a gorge in the Kennedy Range, where Mesozoic rocks, 
consisting of sandstone and limestone, are met with. For the next 50 miles, where 
the river is joined by its main tributaries the Lyons, Arthur, Wyndham, Dairie, 
and Dalgety, the Carboniferous formation outcrops in a series of flat-topped hills 
of limestone, shale, sandstone, conglomerates, gypsum, and clay, often very rich in 
fossils, but up to the present no sign of coal has been found. Just above this, 
the river takes a sudden bend to the North, opening out into fine alluvial and 
stony flats, with bold ranges of crystalline rocks rising abruptly from the plains. 
This great bend, which first turns North and then South, forms almost two sides 
of an equilateral triangle, the base of which is 50 miles. In this part of its course 
the river is of great width, and fresh water can be obtained nearly an vwhere at a 
few feet from the surface, in its sandy bed. 
At the head of the Gascoyne the rocks are gneiss, schists, and clay slates 
striking a little to the East of North with quartz reefs and dykes of porphyry, 
while in the bed of the river sandstone and travertine deposits occur, the latter 
often cementing the river gravels and forming a conglomerate, beneath which 
water can nearly always be found close to the surface. 
The plains, stretching away in both North and South from the upper courses 
of the Gascoyne, are for the most part of the desert sandstone formation, strewn 
in many places with fragments of crystalline rocks and quartz, which latter also 
occur as low isolated ridges. 
The Lyons River is the main tributary of the Gascoyne, joining it on the 
Northern side just to the Eastward of the Kennedy Range. From this point its 
course is nearly duo North for a distance of 100 miles over open alluvial plains 
with the Kennedy Range to the Westward, and low flat-topped hills of limestone 
and shale, of Carboniferous age, to the Eastward. 
At. Mt. Thomson, where the crystalline rocks outcrop, it makes a sudden turn 
to the Eastward, flowing over these rocks and granite for 100 miles. 
This river takes its rise in the sandstone table-land between the Toa.no Rano-e 
Mount Labouchere, and the great flat-topped range that forms the water-parting 
between the rivers which flow in a North-Westerly direction, and those which 
flow to the Westward. This table-land is about 1,500 feet, above the sea, and is 
broken in many places by deep gullies, which the streams have cut down to the 
older rocks beneath, and in other places by the obtrusion of bold masses of crystal¬ 
line rocks, which often rise to a considerable elevation above sea-level. 
