The second series of facts which have attracted my attention, relate to the Aborigines.  It is a well known circumstance that the dialects, customs, and pursuits in use among them in the various parts of the continent, differ very much from each other in some particulars, and yet that there is such a general similarity in the aggregate as to leave no room to doubt that all the Aborigines of Australia have had one common origin, and are in reality one and the same race.  If this then is really the case, they must formerly have spread over the continent from one first point, and this brings me to the

Third reason I have mentioned as being one, from which I infer, that there is not an inland sea, viz., the coincidence observable in the physical appearance, customs, character, and pursuits of the Aborigines, at opposite points of the continent, whilst no such coincidence exists along the intervening lines of coast connecting those two points, and which naturally follows from the circumstances connected with the present location of the various tribes in which this is observable, and with the route which they must have taken to arrive at the places they now occupy on the continent. [Note 37 at end of para.] I believe that the idea of attempting to deduce the character of the continent, and the most probable line for crossing it, from the circumstances and habits of the natives inhabiting the coast line is quite a novel one.  It appears to me, however, to be worth consideration; and if it is true that the natives have all one common origin, and have spread over the continent from one first point, I think it may reasonably be inferred that there is a practicable route across the centre of New Holland, and that this line lies between the 125th and 135th degrees of east longitude.  It further appears that there must still be a second route, other than the coast line, in the direction between Port Jackson in New South Wales and the south-east corner of the Gulf of Carpentaria on the north coast.

[Note 37:  Vide Chapter VII. of Notes on the Aborigines, where this subject will be found fully discussed, and the reasons given for supposing the conclusions here assumed.]

If then we have reasonable grounds for believing that such lines of route actually do exist, it becomes a matter of much interest and importance to determine the most favourable point from which to explore them.  My own experience has pointed out the dreadful nature of the southern coast, and the very great and almost insuperable difficulties that beset the traveller at the very commencement—­in his efforts even to establish a single depot from which to enter upon his researches.  The northern coast may, probably, afford greater facilities, but in a tropical climate, where the heat and other circumstances render ordinary difficulties and impediments still more embarrassing and dangerous, it is a matter of deep moment that the expedition for interior exploration should commence at the right point, and this can only be ascertained by a previous examination.