322 PART SURVEYED BY FLINDERS. 



Swain's Reefs, the individual reefs on the outer edge 

 of the group are scarcely to be distinguished in form 

 from those inside them, although they may have a 

 little more linear shape, and their greatest length 

 run more invariably along the line of the boundary 

 of the group. It is only at their northern extremity 

 that they assume one of the characteristics of a true 

 barrier, that of rising like a wall from a deep and 

 almost fathomless sea. 



The inside, or south-west boundary, of the group 

 called Swain's Reefs, was traced to lat. 21° 50' ; it 

 left a space of fifty or sixty miles wide between it 

 and the land, clear of reefs, and with a depth of 

 30 to 50 fathoms. From a little beyond this point, 

 or north of 22°, the reefs were examined along 

 their inner boundary by Captain Flinders, as far as 

 lat. 18° 30'. He endeavoured, in vain, to find a 

 passage through them out to sea in the intermediate 

 space ; and in all probability they are a wide and 

 strong body of reefs, and their outer edge may pro- 

 bably run from that of Swain's Reefs through Lieut. 

 Vine's Horse-shoe Shoal, to lat. 1 9°, or thereabouts. 

 In lat. 18° SO', Captain Flinders found a large gap 

 in the Barrier, through which he passed out to sea. 

 It was at least twelve miles wide, but a bank of 

 soundings ran along it, on the edge of which he 

 got bottom in 58 fathoms. From this gap, as 

 far as lat. 16° 40' (a space of about 120 miles), the 

 form and condition of the Barrier is unknown; 

 north of the latter point, however, it has now been 



