general bearing of the whole epoch on Evolution so far as its 

 plant-remains go. The most beautiful leaf-beds belong to 

 the Upper Miocene, and are best seen at Oeningen, in the 

 valley of the Rhine, between Constance and Schaffhausen. 

 They have been explored by the late Professor Heer, whose 

 noble work on the Tertiary Flora of Switzerland will form an 

 imperishable monument to his name. At this spot there seems 

 to have been a lake, probably fed by springs with water 

 unusually charged with carbonate of lime. Along the margin 

 of this lake a series of very fine marls were deposited, often 

 as thinly laminated as the pages of a book. In these strata 

 an astonishing number of leaves, fruits, and insects have been 

 preserved. A small collection of them is to be seen at the 

 British Museum, now in South Kensington. To give some 

 idea of the completeness of the record for this particular 

 epoch, it may be pointed out that of a kind of camphor-tree 

 (Prinos Lavateri) distinct sprays are found with flowers, fruit, 

 and leaves; that the well-known key-fruit of the maple 

 abounds, together with countless leaves ; that on some remains 

 leaf- fungi can be detected just as they now are developed in 

 autumn ; and that the time of year when the deposit was made 

 can often be inferred from the shoot being in its vernal or 

 autumnal state, and from the ants having their wings or not. 

 What, then, was the vegetation that surrounded this Swiss lake 

 at a time before the Alps had undergone their last elevation ? 

 First of all, not one plant of the present Swiss flora has been 

 found. Secondly, the vegetation was very rich in trees, and on 

 the whole had a resemblance to that of Florida, Mexico, Aus- 

 tralia, and Japan. The number of woody plants was very great 

 for so small an area. About 180 are known. These include 

 swamp cypresses, evergreen oaks, laurels, elms, maples, 

 acacias, liquidambar, and seven kinds of palms, including 

 one (Sabal) similar to that now growing in the valley of the 

 Mississippi. On the surface of the lake floated water-lilies, 

 around its margin were reeds and rushes. The ferns are pre- 

 cisely the same as our recent ones, only of a sub-tropical type, 

 such as Lygodium a climbing fern, and Osmunda lipnitum. 

 But it would be tedious to give anything like a complete list 

 of the still-existing genera which are found in these strata. 

 Every one who examines the remains must be forcibly struck 

 by the extreme distinctness of the generic type ; for, great 

 as must be the interval which separates us from these suc- 

 cessive Miocene floras, all the genera are obviously as distinct 

 from each other then as now. 



More than this, so great is the constancy of type in many 

 cases that Professor Heer gives a list of plants in which 



