_:b1216764 . _:b1216764 "A large closed depression draining underground, witha flat floor across which there may be an intermittent or perennial stream and which may be liable to flood and become a lake. The floor makes a sharp break with parts of surrounding slopes."^^ . _:b1216764 . _:b1216764 "web:http://wasg.iinet.net.au/terminol.html"^^ . _:b1216764 .