15 
These hills are generally separated from the coast by large alluvial plains, 
intersected here and there by quartz reefs (as at Mallina) and huge outcrops of 
rock, forming a bold rocky coast, as at Cossack, where the hornblende rocks are 
largely developed, traversed by veins of actinolite and tourmaline. 
The Fortescue is about 200 miles in length, taking its rise in the great 
Palaeozoic table-land, and flowing in a course nearly due West, over a large alluvial 
flat, between the Hamersley Range to the South, and high table-land country to 
the North; the creeks which flow from this latter are fed by springs, which cause 
this river to be always trickling. 
At about 30 miles from the coast it leaves the table-land, flowing across low 
alluvial plains in a Northerly direction, discharging its water into mangrove 
swamps a little South of Cape Preston. 
Between the Fortescue and the Ashburton Rivers, at the heads of the Robe 
and Cane Rivers, there is a Paleeozoic and basaltic table-land, which in places is 
much broken, consisting of flat-topped hills which rise from alluvial plains. 
The Gascoyne District. 
This district extends along the coast from Point Cloates South to a point a 
little South of Sharks Bay and Eastward to the boundary of the Colony, embrac¬ 
ing the most of the Ashburton River, the Lyndon, Minilya, Gascoyne, and its 
tributary the Lyons, the Wooramel, and Upper Murchison River. 
The Ashburton River is about 500 miles in length, discharging its waters on 
the North-West coast, about 60 miles West of the North-West Cape. 
For the first 50 miles of its course it runs in a nearly South direction through 
a low broken table-land country, of Mesozoic age, then striking more to the East¬ 
ward for the next 50 miles, passing through a belt of Palaeozoic rock to its junction 
with the Henry, Duck Creek, and Hardy, where it spreads out into large alluvial 
plains, often 20 and 30 miles in width, with here and there low ridges of clay slate, 
and quartz, and bold range masses of harder rock standing up above the flat here 
and there. 
For the next 150 miles the river continues its course to the South-East, 
through rough slaty country, which closes it in some places for a few] miles, 
causing it to flow in a deep channel, often almost a gorge, and then opening out 
again into large alluvial flats. 
This belt of country along the river has proved very rich in gold; it is pro¬ 
bably of Silurian ago, from its similarity to the gold-bearing country of Victoria, 
hut this is uncertain at present. This river takes its rise far away in the sandy 
table-land of the interior, but very little is at present known of this country. 
Although of great length, this river flows in a comparatively small but deep 
channel, in which large water-holes are met with, which are the mainstay of this 
country. 
The Henry, one of the main tributaries of the Ashburton, takes its rise about 
100 miles to the South, near the great bend of the Lyons, in the Barlee Ranges. 
In the upper part of its course it flows over a large plain, with here and there 
exposures of granite and crystalline rocks, but, on approaching a point 30 miles 
above its junction with the Ashburton, where the range closes in, it flows in a deep 
gorge between cliffs of crystalline limestone, from which many heavy springs break 
out. Below this it flows in a deep channel, with large alluvial plains on either side, 
and here and there outcrops of rock or flat-topped limestone hills. Duck Creek and 
the Hardy River join the Ashburton a little higher up on the North side; they now 
near their junctions over low alluvial plains, with here and there ranges standing 
np from them in their lower courses, but, higher up, flowing through rough slatey 
and granite country, taking their rise in the great table-land at the head ot the 
Fortescue River. 
