II) 
ridges running parallel with the coast. As a matter ol' fact there are one or two ridges, of later 
age than those further inland, which run parallel to the existing coast-line for some distance. 
These are best seen some 10 miles S. of Double Island Point. The inner ridge is usually higher 
than the one nearer the shore, and along the shore itself new and living ridges are struggling to 
raise themselves in places. These coastal ridges disappear towards both extremities of the beach. 
A study of what is happening on the beach to-day may help to explain the marginal ridges. The 
sea is undercutting the shoreward faces of the dimes, forming steep cliffs, from which large patches 
of soft sand are constantly slipping. This material is being redistributed. Tt banks up across 
the mouths of gullies, which run out on the coast, and tends to form new ridges on the beach in 
front of the older dunes. 
Viewed from above, as from the summit of the lighthouse tower at Double Island Point, 
the old dunes can be seen forming parallel ridges which run almost E. and W., or approximately 
at right angles to the coast and parallel to the southern margin of Wide Bay. Passing over the 
coastal dunes some 10 miles to the S. we find again that the ridges tend to run inland rather than 
to follow the coast. Some nice little problems in recent geology and physical geography are waiting 
to be worked out in this region. 
The result of the distribution of the dune ridges described above is that the gullies between 
the inland dunes, which are the natural lines of drainage, are frequently blocked by transverse 
barriers, formed by the coastal dunes, and form warm, damp, swampy depressions in which grow 
large trees and palms, together with a dense undergrowth of canes and creepers, the whole resemblin')- 
the tropical jungles of the coastal swamp areas of New Guinea. The barriers being formed of 
loose porous sands, the drainage waters soak through to the coast and emerge between or just 
above tide levels as bubbling springs in the beach sands or as soaks of fresh water which may cover 
large areas. These soaks frequently carry with them a large percentage of iron oxides in partial 
solution, which form characteristic greasy, red, iridescent films and deposits which have frequently 
been mistaken for seepages of petroleum. 
2. Gully stowing section of Old Dune Deposits near Boring Sites, 
Laguna Beach. 
Photo., L. C. Ball. 
