160 
Geology of Sydney. 
Macrotamiopteris , illustrated in Fig. 4. One plant 
which must have been extremely common is shown in 
Fig. 30. The name (Thinnfeldia odontopteroides) is 
certainly unfortunate, being neither elegant nor appro- 
priate; but it may be considered quite a characteristic 
fossil, for wherever the Hawkesbury Sandstones occur 
there this plant is found. It is not quite certain whether 
it was a fern or a conifer, but of its abundance there 
can be no possible doubt. Magnificent impressions 
have been found in the sandstones and shales around 
Sydney, at Mount Victoria, and as far west as Dubbo. 
The Dubbo specimens are remarkably fine, and some of 
them have been figured by Feistmantel in his Mono- 
graph on the Fossil Plants of the Goal-bearing Rocks 
of Eastern Australia , although their true locality is not 
mentioned in that work. Recognisable specimens may 
be expected almost anywhere, but they are particularly 
abundant on the thin shales interbedded in the sand- 
stones around Sydney, and in the shales exposed in the 
cliffs at Narrabeen. Some of its fronds measured three 
feet in length, and the great abundance of these 
imprints shows that the plant must have grown plenti- 
fully around the old lagoons that are now beds of 
shale. Writing of Thinnfeldia , the late Rev. J. E. 
Tenison- Woods, says : — 
“ The genus Thinnfeldia is known by its stout, 
strong, and fleshy leaves. The pinnules are stiff* and 
shining, and of varying shape. The raehia forks 
frequently, the leaflets are oblong, oval, and united to 
one another by the base on the rachis. There is a 
