1922] on Biological Studies in Madeira 563 



maritime enterprise of the Portuguese race is due, and to whose 

 initiative in the very dawn of navigation the world-wide penetration 

 •of these people testifies. The Navigator's mother was an English- 

 woman we may proudly say. But the discovery of the archipelago 

 of Madeira was a stepping-stone to greater things, for here it was 

 that Christopher Columbus, studying the charts of Peristrello, his 

 father-in-law, a pioneer in Portuguese adventure, and an early 

 Governor of Porto Santo, observed the flowing sea-currents and the 

 evidence they brought of land and life beyond the Western horizon. 



In reviewing the means by which the Madeiras were colonized by 

 their rich and comprehensive flora and Testacere, we may at once omit 

 'the participation of any human agency in this work. The islands 

 were untouched by man when first revealed to the Portuguese, even 

 if we accept the legendary story of an English couple being cast 

 ashore here a hundred years before the sailors of Prince Henry took 

 possession, and it is extremely unlikely that the profound solitude 

 and isolation had ever been violated by human feet. 



It is, moreover, evident that the characteristic features in the 

 local flora had developed long before the active volcanic forces of 

 construction had subsided into the long period of slumber we are now 

 experiencing ; and in this connection I have examined with some care 

 a fossil leaf bed on the north side of Madeira proper, whose preserva- 

 tion has been probably due to the subsequent protection of volcanic 

 ■ejecta, forming in numerous strata a mound 120 feet high, the whole 

 mass being capped with a vast mass of trachyte, which originally was 

 in places quite 50 feet thick. The leaf bed, which was buried 

 beneath all this mass in varying strata, contains well-preserved leaves 

 of the local giant-leaved Rubus, the seed-cases of Glethra arborea, 

 and other evidence of the stabilized evolution of the native flora in 

 the early history of these rocks. One incident alone — viz. the com- 

 plete disintegration and disappearance of the thick trachyte deposit 

 which is now traceable only by markings on the adjacent columnar 

 basalt — will fairly illustrate the time requirement for any important 

 geological change. 



You will notice by this specimen that the trachyte is a substantial 

 stone of enduring quality, and in Funchal you may see stairways, 

 columns, doorways and other lapidary work showing no material 

 wear or disintegration after a century or two of exposure to the same 

 •conditions of erosion under which the stone cap of the Porto da Cruz 

 leaf bed has wasted and is gone. Hence, taking the trachyte as 

 indicative of the ebb of time, we need set no niggardly limit to the 

 ages required for the establishment of the specialized forms of life 

 presented to us in this district. 



But if we know something of the ages which have been concerned 

 in colonizing these remote rocks, we are none the less astonished at 

 the completeness with which plants in their natural orders are repre- 

 sented in Madeira, and at the vast number of new and absolutely 



