Coal- Beams of Van Diemens Land. 121 



of Bridgewater, exposing a thickness, I should think, of not 

 less than 200 or 250 feet. 



Towards the lower portion of the section the beds are 

 more solid, hard, compact, and crystalline, and much less 

 mixed with arenaceous matter : the organic contents are 

 also somewhat different, numerous large univalves occurring 

 which are not found in the upper beds, and corals being less 

 abundant. 



Where last seen these beds pass under thick masses of 

 gravel and superficial detritus, and are nearly horizontal. 



At Bridgewater we again come on the white claystone 

 rock of New Norfolk, exposed in large quarries, which have 

 been excavated to obtain material for the formation of the 

 long embankment which here crosses the Derwent. 



The beds dip (E. 10° S.) 



From this point to Hobart Town, wherever the stratified 

 rocks are exposed, they appear to consist of the soft sand- 

 stones and shales of the carboniferous series. 



Thus, between New Norfolk and Bridgewater there 

 appears to be an anticlinal axis, the lowest exposed beds of 

 which consist of a series of sandy and calcareous strata, 

 replete with fossils, and which, with the overlying clay-rock, 

 together near eight hundred feet, forms, I believe, in this 

 portion of the Derwent the base of the true Coal-measure 

 series. If coal-beds exist lower, they must be underneath the 

 lime-stones ; and, therefore, any attempt to discover them 

 should of course be made where the lowest beds of that 

 series are exposed on the surface. 



From all I have seen, however, I believe these fossiliferous 

 limestone beds to constitute the base of the whole carboni- 

 ferous series of Van Diemen's Land ; and, therefore, any 

 attempt to find Coal underneath will always prove fruitless. 



The diagram, PI. I. fig. 1, shows the probable sequence 



Q 



