THE BASALTS OF IEELAND AND SCOTLAND. 661 



Lower Eocene period ; that the increasing temperature drove 

 it north ; that once established in the latitude of Greenland, it 

 followed the then existing coast-line across the Atlantic ; and, 

 lastly, descended into America when the decreasing temperature 

 of the Miocene rendered a southerly move imperative. It seems 

 to have increased in size and strength, and, as a recent fern, is 

 described by Newberry as varying " in the size, outline, and ner- 

 vation of the sterile frond, from 6 inches to 3 feet in height, from 

 a finely reticulated to an open dichotomous nervation ; from a 

 bi pinnate frond with remote obovate pinnules to a pinnate form 

 with wave-margined pinna? and broadly alate rhachis." He has 

 named the American fossils Onoclea sensibilis fossilis, finding 

 that the recent species "plainly includes all the characters of the 

 fossils before us"*. It adapts itself to a considerable range of 

 temperature, growing in America from Florida to Canada, and in 

 Asia from the Amur to Japan and Manchuria. Further descrip- 

 tions and illustrations of the American fossils by Prof. Newberry 

 are to be published. 



The Ferns from the Lough-Neagh deposits belong to an 

 altogether different and much newer horizon. The palaeonto- 

 logical evidence, so far as it is available, points conclusively to 

 the Middle or Upper Eocene as likely to be about their true age, 

 while the stratigraphical evidence warrants us, I believe, iu 

 including them in the Eocene basaltic formation. 



It is very significant that these, occurring in a later formation, 

 should present us with the first instance of the occurrence of 

 species of the English Eocene in that of North Britain ; and the 

 induction is almost irresistible that the increased temperature 

 enabled them to occupy stations previously beyond their range. 

 The two species are Goniopteris Banburii, Heer, and G. stiriaca, 

 TJnger, both known in Ireland from unique specimens. The 

 latter is one of the commonest plants at Bovey Tracey ; and the 

 former is also met with there, as well as more frequently towards 

 the upper part of the series at Bournemouth. The Lough-Neagh 

 deposits exhibit quit ■ a striking analogy with those at Bovey 

 Tracey; and were we dealing with invertebrate or vertebrate 

 fossils instead of with fossil plants, the community of two such 

 well-marked species as these would be regarded as conclusive 

 evidence of the synchronism of the deposits. 



* Ann. Lye. Nat. Hist. N. Y. vol. ix. p. 39 (April 1865). 



