126 bulletin: museum of comparative zoology. 



Queensland coast with the Australian mainland. The proofs of the 

 moderate subsidence given by Jack only intensify the separation, and 

 furthermore this submergence was followed by an elevation, of which 

 Jack says : "I hold that a great submergence of the eastern coast (as 

 exemplified by Sydney harbor and the Townsville deep drifts) was at 

 a comparatively recent date, succeeded by a movement of elevation 

 which is still in progress." 



Steaming through Whitsunday Passage (Plate XXX.) we got our first 

 fine view of the extensive denudation and erosion which has been going 

 on since cretaceous times along the eastern coast of Australia. In the 

 more southern colonies, New South Wales and Victoria, the peculiar val- 

 leys of the Blue Mountains and the fine harbors which are found along the 

 coast of the former give an excellent idea of the extent of this denudation. 



Moreton Island (Plate XXVI.), the Glassy Mountains, Breaksea Spit, 

 and the passage between Frazer Island and the mainland (Plate 

 XXVII.), are the most southern examples of the formation of islands, 

 the former connection of which with the mainland is still clearly indi- 

 cated. They are still partially connected, as it were, with the main- 

 land, while to the north the islands, islets, and rocks, which undoubtedly 

 once formed a part of the eastern shore, have become more widely 

 separated. They are in a district in which the erosion and denudation 

 have acted more powerfully. 



There is no proof of any extensive subsidence since the cretaceous 

 period, but during that period there must have existed a comparatively 

 deep sea separating that part of Australia which in a general way lies 

 south of the area covered by the desert sandstone formation from the 

 older lands to the north of the present Australian continent. The 

 larger islands are generally nearer the continental shore ; as we go 

 out towards the edge of the Barrier Reef they fast become smaller, and 

 near the outer edge of the reef we only find an occasional rocky islet to 

 attest the former existence at from twenty to seventy-five miles from 

 the present shore line of the outer and eastern edge of that continent. 



The farther east the more and the longer has the shore line been ex- 

 posed to the disintegrating action of the sea. Thus the outer islands 

 and islets first separated from the coast were reduced to the level of the 

 sea long before the inner islands now forming the various archipelagos 

 along the eastern coast of Queensland and within the Barrier Beef wore 

 separated from the mainland. On the flats thus formed, and on their 

 outer edges, corals began to grow, and as the process of disintegration 

 and erosion extended inland the corals followed in the same direction 



