IN THE 'biologia centrali-americana.' 551 



Professor E. W. MacBride, D.Sc, F.R.S., V.P.Z.S., in winding 

 up the discussion, pointed out that there could be no inherent 

 improbability in the existence in Secondaiy times of a land-bridge 

 connecting Soutli Africa and South America, for there was strong 

 stratigraphical evidence for the existence of such a bridge across 

 the North Atlantic. On both eastern and western shores of this 

 ocean two sets of red sandstones with intervening coal-measures, 

 both sets being of extraordinarily similar lithological character, 

 represented the Devonian, Carboniferous, and Permian periods. 

 As we receded from the coast in both directions, westward in 

 America and eastward in Europe, we found that these periods 

 were represented by rocks of quite different lithological characters. 

 Geologists believed that the coastal rocks were produced by the 

 washings from a, North Atlantic continent consisting of granitic 

 I'ock and that this continent lasted till the close of Eocene 

 times. 



