137 



that of tlie German Ocean, interrupted the march of 

 these wanderers to the far West, and debarred an im- 

 mense proportion of them from an entry into Ireland, — 

 which would otherwise have colonized that country 

 equally with our own. 



As regards Professor Forbes' s views of the creation of 

 a vast continent (reachiug far into the Atlantic *) at the 

 close of the miocene epoch, through the upheaved bed 

 of a shallow miocene sea, — a region moreover of such an 

 extent as to have connected the various island groups 

 between the Fucus bank and the shores of the Old 

 World, not only with each other, but with a Mediterra- 

 nean province, Asturias, and even the south-west of 

 Ireland, — I must be content to pass them by, hazarding 

 only a few crude and desultory remarks. So large a 

 question, iudeed, cannot be safely handled without 

 a corresponding amount of data, iu all departments of 

 natural science, to reason from, — which I do not possess: 

 still, if a speculation from entomological premises, per 

 se, be not altogether worthless, I would poiat to the 

 conclusions (lately adverted to) which my Madeiran 

 researches have forced upon me, concerniag the direc- 

 tion of the former insect migrations, — inferences which 

 are, from first to last, of necessity erroneous, if the 

 requisite medium for transit (into South-European lati- 



* " My own belief," says Professor Forbes, " is, that the great 

 belt of gulf-weed, ranging between the 16th and 45th degrees of 

 north latitude, and constant in its place, marks the position of the 

 coast-line of that ancient land." 



