GEOLOGY OF TASMANIA. 71 



shales to 894 feet, without reaching bottom. This is equi- 

 valent to about 200 feet below sea-level. At Beaconsfield, 

 palaeogene clays rest in a gutter of palaeozoic rocks, 270 feet 

 below sea-level, and their lowest layer is rich in fossil fruits 

 (Sjjondylostrobtis, Platycoila, Cordia, &c.), and a leaf of 

 Ginnamovium has been recorded. Fossil conifers are also 

 found in this bottom clay. In the N.E., the high 

 plateau of sand and gravel, containing alluvial tin-ore, near 

 Derby and Branxholm, which is capped with basalt, marks 

 the ancient course of the Ringarooma River before it was 

 choked with lava, and diverted to its present channel. At 

 Burnie, in a white pipeclay below the basalt, imprints of 

 leaves of Eurojaean types have been found. At Waratah, 

 leaf-imprints have been obtained from a greyish Tertiary 

 sandstone, beneath 45 feet of basalt, at a height of 2000 

 feet above sea-level. These leaves have been determined 

 by Mr. R. M. Johnston, as follows : — Eucalyptus hayseri 

 n.s., Laurus sprentii n.s., Quercus bischofensis n.s., Ulmus 

 tasmanicus, Cycadites microphylla n.s. Leaf-beds of similar 

 age, and containing impressions of Ginnainomum, also occur 

 in the cliff at Strahan. Tertiary leaf-beds also exist in the 

 tin-drift in Thureau's deep lead at St. Helens. The basin 

 of the Derwent exhibits a series of Tertiary sands and clays, 

 the latter of which, at Cornelian Bay, Sandy Bay, One Tree 

 Point, Glenora, &c., contain the usual impressions oiQuercus, 

 Fag us, Salix, Gmnainomuin, he. The so-called travertin, 

 at Geilston, contains Cypris alhuryana (Johnston), conifer 

 stumps, and leaf impressions of Quercus, Fagus, Salix, Cin- 

 namonium. At the head of Oyster Bay, near Swansea, 

 there are Tertiary, probably palaeogene, clays, which contain 

 a good deal of clay ironstone. Beds and seams of lignite 

 occur at Dilston, Evandale Junction, Kelly Basin, and other 

 places in Tertiary areas. At Kelly Basin, siich beds con- 

 tain fossil resin, and at Evandale Junction the beds also en- 

 close resin globules. 



3. At the close of the Palaeogene, a great outpouring of 

 basaltic lava took place, and this rock is very general 

 throughout the Island, though rarer on the West Coast. 

 Three types of basalt have been met with up to the pre- 

 sent: — 1, olivine basalt; 2, nepheline bearing olivine 

 basalt; 3, melilite basalt, associated with nephelinite. The 

 first type is the common variety of the Island. It has over- 

 spread the Campbell Town and Conara plains, and widely 

 conceals sediments in the Launceston Tertiary basin. Its 

 mineral constituents are uniformly felspar -I- augite -f- 

 olivine. Its texture is doleritic on the coast N. of Le- 

 frov, at Mount Horror, at Paddy's Peak, Hampshire. Fine 



