l xvi INTRODUCTION. {Prior Discoverie s 
Dampier. New Holland was separated from the lands to the southward, by a 
1699- strait; " unless," says he, " the high tides and indraught thereabout 
" should be occasioned by the mouth of some large river ; which 
« hath often low lands on each side of the outlet, and many islands 
" and shoals lying at its entrance : but I rather thought it a channel, 
" or strait, than a river." This opinion lie supports by a fair induc- 
tion from facts ; and the opening of twelve miles wide, seen near the 
same place by Vlaming's two vessels, and in which they could find 
no anchorage, strongly corroborated Dam pier's supposition. 
Later information had demonstrated, that the supposed strait could 
not lead out into the Great Ocean, eastward, as the English navigator 
had conjectured ; but it was thought possible, that it might com- 
municate with the Gulph of Carpentaria, and even probable that a 
passage existed from thence to the unknown part of the South Coast, 
beyond the Isles of St. Francis and St. Peter. 
But whether this opening were the entrance to a strait, separating 
Terra Australis into two or more islands, or led into a mediter- 
ranean sea, as some thought ; or whether it were the entrance of a 
large river' there was, in either case, a great geographical question 
to be settled, relative to the parts behind Rosemary Island. 
If Tasman's chart were defective at De Witt's Land, it was likely 
to be so in other parts of the same coast ; where there was no 
account, or belief, that it had been examined by any other person 
further north than the latitude i6i-°. An investigation of the 
whole North-west Coast, with its numerous islands and shoals, was, 
therefore, required, before it could enter into the present improved 
systems of geography and navigation. 
The chart of the West Coast, as far south as Rottenest, was 
founded upon much better authority ; but for its formation from 
thence to Cape Leeuwin there were no good documents. In this 
part, there was room even for discovery ; and the whole coast 
required to be laid down with more accuracy than had been attain- 
able by the Dutch navigators. 
