ROARING CAVERNS

Otago Witness, Issue 3525, 4 October 1921, Page 27

ROARING CAVERNS

STRANGE A'ENTS TO UNDERGROUND I RIVERS. | I (From Our Own Correspondent.) SYDNEY. September 20. | Sir Edgeworth David, Australia’s foremost | geologist, who has just compel ted cut investij gat ion of a great artesian basin which lias j been discovered in an arid part of AVestern | Australia, covering the Nallabor Plains, | Hilda region, tells of sin-c remarkable caverns of great extent which honeycomb the I earth. On the surface, lie says. ’ the plain | appears to be quite flat and featureless, but { when examined more closely il is found that | li.cre mid Dime are funnel-shaped hollows j which terminate often in raves of vast extent. ! A cave of this kind occurs about 14 miles ! north-north-west of Eucla. It can be ! descended to a depth cf over 200 ft. the roof lin places being some 10ft or 50ft high. In ; file lowest oave is a large poo! of crystal i clear water which has been sounded and j found to be about 05ft ch p. This water is j somewhat saline, not as a result of sea water I penetrating so far inland, for it is above | sea-level, but because of the water contain- | ing salts dissolved out of the marine limei stone. The whole area is more or less honey- | combed beneath the surface with eiilier large j caves or smaller tortuous underground chanj ne's and cavities communicating, sooner or j later, with a large cave. These caves and 1 cavities form reservoirs in some cases for 1 water, and in all cases for large quantities • of air. AVhen any change takes place in a i barometric pressure at tiie surface of the ! plains, remarkable things occur. li the pres- : sure is lessened owing to a fall in the baro- | meter, air rushes out from the funnel-shanect | mouths of the caves or the small openings !of the wells. Tito air rushes outward with i a great roaring sound, the current being : strong enough to blow one’s hat up into the 1 air. AVhen a high pressure supervenes after | a low pressure the air current is reversed | and there is a strong indraught down tho I wells and cave mouths. Under these vast plains the subterranean water flows at two ! very distinct, levels.