22 THE SUKKEN ISLANP OF ATLANTIS. 
Flora Tertlaria. Flora Atlantica, 
Ijaurus princepsj Heer. Laiirus Canariensis, Sm, 
Clethra Teutonica, U. Clethra alnifolia, Linn. 
Olea Obiris, U. Olea excelsa, Ait. 
Salix varians, Gopp, Salix Canariensis, Sm,^ 
• We can therefore not "be surprised if the Tertiary plants of Madeira . 
agree with the present vegetation of the Atlantic islands; on the con- 
traiy, as the same is the case iu North America^ it would be singular 
if it were otherwise. The threat bridge Avhich connected the two con- 
O^^"" "-'-^D 
tinents must therefore have led by way of these islands, as well as by 
that of Iceland. At present it is impossible to speak more precisely on 
this subject. Perhaps a more accurate definition of the extent and con- 
nection of this central continent might be given by availing ourselves of 
the well-known soimdlngs taken in the Atlantic Ocean ; but it would 
always be a difficult and dangerous undertaking, and we might be 
thrown by the waves of this treacherous ocean of speculation from one 
hidden rock upon the other. It also seems to be, in more than one 
respect, unsafe to regard the Sargassum sea as the remains of a former 
coast-line. At present we must be content to know that during the 
Tertiary period an intermediate continent, which we shall call Atlantis, 
really exi&tedj and that it extended northwards as far as Iceland, and 
southwards beyond the present Atlantic islands. But any attempt at 
tracing its exact confif^uration must be re^carded as ideal. 
^^O -"«X^V ......*. ..^.. ^» v.^ 
It would be highly interesting to know the fate which this continent 
afterwards experienced, until it altogether disappeared, a few islands 
only remaining behind. Atlantis assumed, without doubt, the form of 
an island, separated from both continents. Bat how long Atlantis 
existed as an island has been as little ascertained as its exact extent. 
r 
It is well known that the Tertiary period, rich in plants and flowers, 
was succeeded by evil days, putting a stop to all life. The European 
Tertiary group of islands had by rising gained considerably in extent, but 
for this very reason lost much of its mild insular climate.* The cur- 
* Of 27 of the fossil plants found in tlie lignite beds of St. Jorge, Madeira, 
7 have already died out. See O. Heer's ' Ueber die Fossileu Pflanzen tod St. 
Jorge, Madeira,' inN. Denkschrift der all. Schweiz. G-esellschaft, xy., and Tert. 
"Flora der Schweitz, iii. 
t Ileer (Tert. Fl. d. Schweiz, ii. p. 333) thinks it probable that the tem- 
perature of the Lower Miocene period was about 9^ C, and the Upper Miocene 
T C. {i. e. S"" C. mean) higher than that of present Central Europe. 
