1814 
president’s address. 
flams which had previously penned up their swamp waters, and so 
destroyed the means by which a record of future developments 
might have been preserved.* 
Such a period of excessive precipitation is also indicated by the 
Hawkesbury sandstone, a fluviatile formation of considerable 
extent and duration. The ' flora is little different from the last, 
but the rivers and lagoons of this region swarmed with Ganoids, 
which were preyed upon by those Crocodile-Tadpoles known as 
Laby rinthodonts. f 
I suppose this Hawkesbury series to be the latest of all our 
Mesozoic freshwater deposits, and therefore to lie in a higher 
horizon than even the latest of the Ipswich coal series, whose 
apparent passage by undistinguishable stages into the Cretaceous 
of the Rolling Downs, Paroo, &c., seems very difficult to under- 
stand. If, however, such a gradation from the lowest to the 
highest Mesozoic does really occur in this region, we must regard 
the formation of the Hawkesbury and Wianamatta beds as an 
episode in the story. They are certainly later, but very little 
later (as is shown by their fossil ferns) than the Clarence River, 
Ipswich and Mersey formations. 
In Lithological as well as in Geographical relations they corres- 
pond closely to the Triassic of Europe and America, with which 
their Labyrinthodont remains also unite them.* 
*No change however of importance seems to have taken place until the 
immigration of the Marsupial Fauna and the Tertiary Flora of the Austra- 
lian region. No record of these has as yet been discovered, but we may 
with some probability refer them provisionally to a period immediately 
previous or immediately subsequent to the great cretaceous formation of 
this continent. 
I I am disposed to think that the Fishes of the great Gosford haul are in 
part of a Liassic type, a circumstance paralleled by the concurrence of Liassic 
fish with Triassic Amphibia and Reptiles in the Uppermost Gondwanas. 
The explanation would appear to be that the fish fauna known as Liassic in 
Europe partly originated in the vast river systems of the South, more or 
less contemporary with the Northern Trias, out of which the great Sand- 
stone plateaux of Africa, Australia and India were gradually built up. 
iThere may also have been, in such sandstones as these, local re-formations 
as in the beds of streams or lagoons, composed of the same materials, and not 
