BV W. H. CLKMES, B.A., B.fcC. 37 



bedded in the granite, showing conclusively that they 

 belong to an earlier age, but to what age is a matter for 

 future investigation. Permo-Carboniferous limestones are 

 resting unconfonnably above them, and, on the far side, 

 come down below sea-level, the granites having finally 

 disappeared. Thev continue round the coi-ner of Cocks- 

 comb Head and form a huge semi-circle of cliffs extending 

 almost to Cape Boullanger and the He du Nord, which 

 are of diabase. These cliffs are the finc3t example of the 

 Lower IMarine beds that we have in Tasmania. They are 

 regular and almost horizontal, though one or two examples 

 of lenticular deposition are apparent. There are no strik- 

 ing examples of faulting or deformation sUch as appear at 

 Eaglehawk Neck and other localities. The cliffs slope 

 down gradually to the west from a height of about 1,000 

 feet, Avith flat ledges underneath almost buried in a huge 

 talus of fallen blocks, some of which weigh many tons. 

 These rocks and the cliffs around them are studded with 

 fossils, brought into relief by weathering, and are simply 

 one solid compact mass of shell-remains, among which the 

 Eurydesmas with their thick globose forms predominate. 

 "Blocks of 40 and 50 tons weight seem to be simply made 

 up of a compacted conglomerate of this genus' (R. M. 

 John^iton). The basal beds are the usual grittv iiiuastones 

 more highly studded than usual with ice-borne detritus ; 

 some of the granite blocks embedded in the mud of this 

 old sea-floor must weigh many tons. Their angular nature 

 shows that they have been transported bv ice-action, as 

 that is the only agency which could have carried thom 

 for such a distance and preserved their shape intact. The 

 way in which the surroiuiding mud has been pressed up 

 around their edges aUo proves that thev have been drop- 

 ped from melting floes and sunk to their present resting 

 place. 



Throe zones are represented : — 



1. Eurydesma Zone. 



2. Fenestella Zone. 



3. Crinoidal Zone. 



The first two zones have been well described bv the 

 late R. M. Johnston in his Geology of Ta.'-inania and so 

 I need not elaborate on them here. 



The principal families represented in ihc tir^t zone 

 are Spiriferx, rachi/donnt^, Enrydf-xma , Xotomya, 

 Avicuh/jerfeii, Sfenopora, and Favosites. In the second the 

 Feney-lfUas and Protorcfeporo are interspersed with 

 Spirifrrx, Pnu/iiriiis, Stroplialoi^ia, etc. The Crinoidal 

 Zone is composed almost entirely of a comjiacted mass of 



