18 



Fachydomus and Froducta in great abundance, with many 

 other well-known Upper PalsBvOzoic fossils. The resiniferous 

 shale or dysodile of the Mersey, has also been proved 

 by Mr. G-ould to belong to this series. These coal mea- 

 sures have not yet been recognised as existing West of the 

 Leven, having probably been removed by denudation. They 

 may, however, be met with as the settlement of the land ad- 

 vances southwards from the coast. 



The horizontally bedded conglomerates and breccias of very 

 variable character and uncertain age which occur at intervals 

 between Port Sorell and Table Cape appear to come next in 

 geological order, but may belong to the last named series of 

 rocks. They have occasionally been tilted and broken 

 by intrusions of basalt, and perhaps of trap also, but this 

 is less certain. They are chiefly composed of rolled pebbles 

 and angular fragments of the Primary rocks and the plutonic 

 rocks associated with them, and are usually held together by 

 a strong silicious cement. At the mouth of the Inglis this 

 formation is especially interesting. Large angular blocks of 

 granite and porphyry, the former sometimes weighing several 

 tons, together with rolled pebbles of many of the Primary 

 rocks, are here seen embedded in a fine grained mudstone ; 

 this being evidently derived from the denudation of some 

 of the softer slates, and deposited as mud on the margin or in 

 the bed of some ancient river or estuary, which occupied a 

 basin with nearly the same principal boundaries as the modern 

 Inglis. These massive blocks of granite and other rocks 

 which are not now found in situ within several miles of their 

 present position, I consider to furnish more conclusive evidence 

 of glacial agency in the geological history of Tasmania than I 

 have met with elsewhere, and they strongly corroborate the 

 testimony afforded by the seemingly erratic boulders which 

 occur at various points in the basin of the South Esk. The 

 age of this conglomerate is doubtfal. It underlies unconform- 

 ably the Tertiary freestone, which has been determined by 

 Professor M'Coy to be of Miocene age, and it contains boulders 

 derived from rocks which are certainly not older than the 

 Lower Carboniferous or Devonian period. In the mudstone 

 which forms the matrix of the transported boulders no fossils 

 have yet been discovered, and the chance of finding them 

 is occasionally lessened by the jointing and rude cleavage 

 which sometimes traverses even the hard pebbles of chert, 

 quartzite, &c., contained in it, and almost entirely destroys the 

 traces of original bedding. It is right to mention that some 

 detached portions of conglomerate, apparently belonging to 

 the formation which I am now describing, have some of the 

 peculiar characteristics of the conglomerate which belongs to 



