Grilled barramundi was very tasty, very tasty indeed. It is a white fish, but it has the meat-like consistency of tuna. Unfortunately it was rather boringly accompanied by chips (I.e., French fries), which is the accompaniment of choice here in Australia, and that took away a little of the glamour of a fancy dinner.
Talking about fish, I forgot to tell you that in the brackish waters of the estuary you also find the archer fish, a dumpy guy with the uncanny ability of squirting a powerful jet of water at insects and small crabs standing as much as a meter above the water on the roots of a manglar, strongly enough to topple them in the water where they are greedily devoured. Interestingly, this instinctive behavior has to be honed over the life of the fish; young fish often miss their mark because they do not account for the refraction of the image of the crab, but as they grow older they learn to take account of the refraction and eventually become ... deadly archers. I know, because I have seen them at work!
Today I spent exploring the Litchfield National Park, a good 75 km south of the estuary. It is what I call the baby Aussie brother of the Grand Canyon National Park, in that it is a plateau capped by horizontal sedimentary rocks, uplifted in recent geologic time. Although it is not cut by a mighty river like the Colorado, the infiltration during The Wet recharges it sandstone layers with enough water that base flow can sustain the flow of several streams that tumble off its edges to form beautiful waterfalls and swimming holes. The Parks System keeps a close eye on crocs in the swimming holes, and promptly remove any they find before certifying the swimming holes as "safe". Australians, of course, love to go go swimming, which makes this park tremendously popular.
The Litchfield Plateau is formed by a basement of Proterozoic quartzites, overlain by a horizontal sequence of fluvial and aeolian sandstones with lamination, asymmetric ripple marks, and faint cross bedding. I am not sure what age they are, but they uncanningly similar to the Jurassic Aztec Sandstone of the Mojave Desert (but they could be Permian or Triassic). Now and then you see some interbedded limestones.
The many streams that issue from the plateau have formed wide floodplains, which appear as beautifully manicured grass ribbons crossing the land. Great place for wollobies to hold hopping races, but hard on any other plants and critters. Except for termites, which have adapted their survival strategy by building particularly tall termite mounds. On a flood plain these termite mounds are not protected by trees from the brutal heat of The Dry, so the clever little animals have learnt to make them tall and fan-like, oriented in a north-to-south direction. Tall because these termites don't have the option of going underground, fan-like because it is a good strategy of heat dissipation, and north-to-south so they present a minimum target to solar radiation during the heat of the day. Clever little buggers!
I did my job as a tourist walking many trails and admiring many waterfalls. We will see if I have any energy left for tomorrow, which will be my last full day in Australia.
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