INTRODUCTION. 7 



Europe and America, as well as the commencement of the warm Tertiary period in 

 Greenland, might have been brought about by the completion of this land connection. 

 Further, the universal gap in the Arctic plant series between the Upper Cretaceous of the 

 Atane and the Eocene (the so-called Miocene) would also be explicable, since the plant-beds 

 below the London Clay are filled with Plane and forms resembling Hazel and Lime, which 

 represent a climate so nearly approximating to that of these latitudes at the present day 

 that no forest of leafy trees could possibly have co-existed with them in the Arctic 

 Circle. 



There have been many attempts to restore the contour of Europe during Eocene and 

 Mi(jcene times. The principal difference appears in its central and southern parts, which 

 were then to a large extent occupied by an extension of the Mediterranean Sea. India 

 appears also to have been an island, and the chief mountain-ranges were hardly upraised. 

 England was united to what then existed of France above water, and the two formed an 

 isthmus which probably stretched towards Denmark and Scandinavia, and served to 

 separate the waters of a then existing North Sea from a sea which extended south to the 

 Mediterranean and Southern Atlantic. The present Eocene Basins of Hampshire and 

 London seem to have formed part of one vast river-delta, which originally extended over 

 portions of France as well ; but, while the whole of our Eocenes are delta deposits, 

 the plant-beds of Europe are almost exclusively lacustrine or tufaceous. Judged 

 from the area and thickness of its deposits, the river which flowed from the west 

 must have drained a land of continental dimensions, and it may well be that the then 

 relatively small area of Europe, Asia, and a part of North Africa, was compensated 

 by a vast stretch of land to the West, upon which the immensely varied Eocene 

 forests, whose remains are to be described, must have succeeded each other. By some 

 means or other there migrated to this continent, as the temperature increased, at first 

 a flora whose predominating types seem to be Australian, and then a flora whose 

 characteristics are essentially Neo-tropical. The latter, at least, were accompanied 

 by a corresponding group of pulmonate MoUusca, a type of which, the gigantic 

 Bulimufs of the West Indies, swarms with its eggs in the Bembridge Limestone 

 of the Isle of Wight. The Australian flora died out, or migrated South again, while the 

 Neo-tropical flora passed across Europe, and seems to have reached finally the East Coast 

 of Asia, where some of the Eocene species still appear to exist. The submarine ridges 

 that have been mapped seem to furnish an explanation of the route that these migrations 

 may have taken, and shadow precisely the connections which the plants independently 

 prove to have existed ; indeed it is difficult to imagine what the banks which traverse 

 the ocean may signify if not either rising or sinking land. From beginning to end of 

 the Tertiary Period the Western Continent, which, notwithstanding the prejudice that 

 this name provokes, may as well be styled Atlantis^ was diminishing while Europe 

 was extending its area. Briefly sketched, these appear to have been the conditions 

 under which the Eocene plant-world, to be described in these pages, existed. The 



