its structure in my own mind. This notion I shall endeavour to convey to the reader. If it should eventually turn out that my speculations and generalizations are incorrect, no one will be more rejoiced than myself at the acquisition of the more accurate and fuller knowledge that shall overthrow them.
In the meantime I would remind the reader that detached observations have a far greater relative value in such a country as Australia than they would have in a complicated country like Europe. When mountain chains and sheets of rock stretch for hundreds of miles without an interruption, or a change in their general character, cursory observations at great distances one from the other suffice to give us an outline of the country. In Russia, in N. and S. America, as in Australia, observations made across one line of country would thus be applicable to great tracts, while in western Europe a series of observations along" any one line might give no information as to the rocks or formations to be met with, even a few miles on each side of it. Australia especially seems the very land of uniformity and monotony, the same dull and sombre vegetation, the same marsupial type of animals, spread over the whole, land from the gloomy capes of the south coast of Tasmania, and the stormy Leeuwin, to the cloudless and burning skies of Torres Straits and Port Essington. The reader will, I think, see reason in the following pages to
