238 Proceedings of the Roycd Society 
At one time this ornithichnite bed, now washed by every tide, was 
(as it is still beyond its influence) covered by many feet of the 
delta alluvium. The river Waipaoa, which formed these extensive 
plains of rich soil, averaging twenty to twenty-five feet in depth, 
now very rarely overflows its banks. Only once, in the memory of the 
oldest native, has it done so to any extent, and this was since the 
settlement of Europeans, on which occasion there was a deposit left 
of half an inch, in some few spots of an inch of silt ; although in 
bygone times, under different cosmical influences, it probably dis- 
charged a much greater volume of water into the bay, at a point 
opposite the island on the northern shore, and left after every fresh 
a larger amount of soil than it does now on these rare occasions, a 
vast time must have elapsed since it left the first layer of mud over 
the sandstone bed. 
Dr. Hochstetter, the accomplished naturalist who accompanied 
the Austrian expedition of 1859, remarks, u These gigantic birds 
belong to an era prior to the human race, to a Post-Tertiary period ; 
and it is a remarkably incomprehensible fact of the creation, that 
whilst at the very same period in the old world, elephants, 
rhinoceroses, hippopotami — in South America, gigantic sloths and 
armadillos — in Australia, gigantic kangaroos, wombats, and 
dasyures were living, — the colossal forms of life were represented 
in New Zealand by gigantic birds.” But whilst these gigantic 
birds have a higher antiquity than even the megatherium, the 
diprotodon, or zygomaturus, and other strange quadrupedal forms 
of life, which have long passed away, or left only puny representa- 
tives, like the aepiornis of Madagascar, which maintained its ground 
down to a late period in that great island, and against men, too, 
singularly, of an allied race to the Maorie, the moa has the credit 
of having held its own down to the present century, through all 
the great changes of scene and climate which have taken place since 
its ancestors stalked over the plains of the southern portion of a 
great land, — the backbone of which, and little more, remains, — per- 
haps with large lacertians for its companions, long after the giant 
marsupials, the contemporaries of its congener * on the Australian 
savannahs, had disappeared. 
* The interesting discovery there of a large fossil bird has lately been made 
known by the distinguished geologist the Rev. W. B. Clarke, who first made 
