306 
removed from the oscillation of the land which pro- 
duced the conditions favourable to the deposits of the 
Lower Coal Measures in such places as the Don, Mersey, 
Stony Creek, and Anvil Creek basins; that while these 
carbonaceous deposits intercalcating and interrupting the 
series of marine beds were being formed in situations 
adjacent to the shores of the old Palsozoic mainland, the 
marine areas, more remote from the land, still continued to 
deposit their marine sediments with an uninterrupted chain 
of marine organic life; and it is quite conceivable, and, 
indeed, in harmony with existing evidence, that the Southern 
and Hastern Marine Beds of Tasmania cover in one unbroken 
series the whole period represented in Australia and in 
Northern Tasmania by the Lower Marine Beds, Lower Coal 
Measures, and Upper Marine Beds; and that the final 
oscillation of land, producing conditions favourable to the 
deposits of the Upper Coal Measures of Australia and 
Tasmania, was the only one which extended as far as the 
South and Hast of Tasmania.” 
The suggestion that ihe marine beds in the neighbourhood 
of Hobart cover in one unbroken series, the whole period 
represented elsewhere by the Lower Marine Beds the Lower 
Coal Measure, and the Upper Marine Beds, has since been 
amply confirmed by my discovery of the Cythere and 
Gangamopteris beds at Porter Hill, near Hobart. The beds 
at this place. unmistakably show a gradual transition upwards, 
without stratigraphical break of any kind, from the common 
limestones restricted to marine organisms to fine sandy shales 
where the marine organisms have altogether disappeared 
with the exception of a minute ostracod. These upper beds 
are replete with plant remains of ferns, chiefly belonging 
to the genus Gangamopteris. The fossiliferous marine 
limestones and mudstones replete with the common forms 
belonging to the genera Stenopora. Protoretepora, Fenestella, 
Spirifera, Strophalosia, Terebratula, etc., are followed by thin 
passage beds of alternating soft dark-brown sandstones, and 
friable shales where most of the common lower forms disappear 
with the exception of Spirifera Tasmaniensis and S. Darwinii. 
In these shales a species of Cythere swarms in the greatest 
number, together with species belonging to the genera 
Modiolopsis, Lellinomya, and Theca. In the same beds, also, 
the plant remains referred to begin to make their appearance, 
and in the uppermost shales the plant remains and an oc- 
casional Cythere, together with the articulated spines, probably 
of a species of Ichthyodorulites, alone are to be found. There 
is httle doubt, therefore, that these upper beds are the equiva- 
lents of the Tasmanite stage or of the Upper Marine Beds of 
the Mersey. 
