310 THE DESERT SANDSTONE. 



met with in the interior and on the coast, from loose drifting sand' 

 of a true eolian character to hardened stone like the Sydney 

 sandstone. At Double Island Point, about 100 miles north of 

 Cape Moreton in Queensland, there is a sand formation some three 

 or four miles on the south side of Wide Bay. The southern 

 boundary of the bay is formed by two somewhat conical hills of 

 scoriaceous rock separated by a long interval of low land from a 

 mass of volcanic rock. All this may have been part of the ancient 

 crater ; but it is now covered with green vegetation and light 

 timber. On the west side there is an extensive development of 

 sand cliffs quite precipitous on the seaward side, varying between 

 100 and 200 feet high. I have already referred to this curious 

 formation in the paper above mentioned on the Hawkesbury 

 Sandstone, (read before this Society May 10th, 1882) in which I 

 deal with it simply as a formation of blown sand without entering 

 into the question of its origin. No one will dispute that the sands 

 in this case are the ash-beds from the volcano extending to no 

 great distance, but being a patch of such thick beds that there 

 would be no way of accounting for them but for the ancient crater 

 which is close by. The cliffs have curious undulating layers of 

 varying thickness forming sinuous lines with laminae of sand, false- 

 bedded and dipping at every angle up to 30 degrees. The layers 

 no doubt mark different periods of activity. They are of various 

 colours, giving the cliffs a ribboned appearance, white, yellow, or 

 ochreous-red. On the surface there is a dense growth of tea-tree, 

 with a few patches where the sand forms shifting dunes of rounded 

 outline and great height. 



In various geological essays of mine, I have referred to a 

 formation on the south coast of Australia, especially between 

 Port Philip and the river Murray, but always in connection with 

 recent volcanic emanations. It is described as a rock of dark 

 brown colour in patches of rough and compact character ; at times 

 it forms sea cliffs of considerable height. At a distance, one would 

 imagine the rock to be divided into large strata, some 14 or 15 

 feet thick, with false-bedded lamination between. The material 

 of the rocks is sandstone, but the surface consists of fragments of 

 shells and marine remains with grains of sand and sponge spiculse 

 intermingled. At one time I regarded this as composed of 

 hardened eolian calcareous sand ; but a more careful microscopic 

 examination has shown it to be an ash-bed, though sometimes it 

 is many miles distant from recent volcanic rocks. Instances may 

 be seen all along the coast, but fine examples near the extinct 

 crater of Cape Grant, at Warrnambool &c. The rocks around 

 Guichen Bay are all tufaceous, in fact there are few parts of the 

 coast which do not show traces of the former activity of Mounts 



