at the Don and Tamar Rivers. 91 
consist of sand, mud, and gravel; and there is, according to 
various reports, a depth of four to seven feet upon it at low 
water, with a rise of tide of from eight to ten or twelve feet. 
It is certain that, whatever the depth may be in the channel 
at low water, this river has ever been considered unfordable 
at the mouth by those who have been constramed to make 
the experiment. 
The length of the estuary, in which there is deep water 
and absolute shelter for vessels, is about six miles. On the 
eastern side, the shore rises rather steeply into a chain of 
rounded hills of greenstone, heavily timbered, and covered 
with a deep-red ferruginous soil. Half-way up the bay, on 
the same side, the basset edges of sandstone, probably car- 
boniferous, appear at the water’s edge, rising into a cliff about 
twenty feet in height, with a dip under the hill to the north 
and east: it would therefore seem that this greenstone range 
reposes on a basis of sedimentary rocks. It is on the eastern 
side of the broad estuary that the deep and nearly straight 
channel runs; while on the western side there is shoal water 
and extensive mud flats, succeeded by densely-timbered forest 
land, which recedes some distance to the westward, with much 
of the same low and flat character. 
A band of greenstone, through which the Mersey has 
found or forced a passage to the Sea, runs along the coast, 
communicating with successive ridges of greenstone, which, 
running inland in a direction nearly south, determine, in the 
main, the course of the principal rivers and streams. The 
distance of the average course of the Don River from that of 
the Mersey is about four miles: at the head of the estuary of 
the latter, the interval is somewhat greater. A line carried 
south-west from the fresh waters of the principal stream of the 
Mersey, opposite the township of “La Trobe,” would reach 
the Don River at or near the point where the Coal crops 
