BY R M. JOHNSTON, F.L.S. 199 



Great lakes have disappeared — lofty mountains have been 

 formed by the reiterated emission of lava, preceded and 

 followed by showers of sand and scoriae —deep valleys have 

 been subsequently furrowed out through masses of lacus- 

 trine and volcanic origin — at a still later date . . . 

 new lakes have been formed by the damming up of rivers, 

 and more than one assemblage of quadrupeds, birds, 

 plants — Eocene, Miocene, and Pliocene — have followed 

 in succession ; yet the region has preserved from first to 

 last its geographical identity ; and we can still recall to 

 our thoughts its external condition and physical structure 

 before these wonderful vicissitudes began, or while a part 

 only of the whole had been completed." 



This remarkable picture of the lacustrine formations of 

 the south of France would be a tolerably faithful descrip- 

 tion if taken with special reference to similar formations 

 of vast extent in Victoria and Tasmania. 



Climate of the Palceogene Period. 



The climate, as evidenced by the rich flora and fauna, 

 has already been discussed, p. 153. It is probable that 

 the climate varied from subtropical to temperate between 

 the close of the Mesozoic and the commencement of the 

 Neogene periods. 



Neogene Epoch. 



Upper Tertiary. — In Tasmania a series of deposits, 

 generally resting either upon the Palseogene basalts or the 

 lacustrine or marine beds. These deposits consist mainly of 

 clays of various shades of colour, sands coarse and fine, 

 ferruginous sands, and, more conspicuously, of gravels and 

 pebbles, frequently conglomerated among which, in many 

 localities, as at Longford, occur a wonderful abundance of 

 waterworn pebbles derived from the sihcified stems of 

 conifers and other fossil trees. The apparent absence of 

 marine formations and of the newer basalts, found in 

 Victoria, render it difficult to mark the upper limits of 

 this division with any degree of satisfaction. The absence 

 of fossils, other than those derived from the lower divisions, 

 also deprives the classifier of the most reliable guidance 

 in such matters. There is little doubt, however, so far as 

 Tasmania is concerned, that there is represented a perfect 



