ANNIVERSARY ADDRESS OF THE PRESIDENT. XCV 



prove efficient only for those countries in which the houndaries of 

 the spaces occupied by the characteristic fossils of the supposed 

 adjacent zones prove to be coincident. 



Dr. Oppel appears to have examined and compared the fossils 

 with very great care, and has pointed out those which pass beyoud 

 the limits of any one zone into the region of another, so that he has 

 done his best to enable every geologist to discuss the subject for 

 himself, and form his own conclusions from the data set before him. 



As the French names of D'Orbigny used by Oppel are not, 

 perhaps, quite familiar to every one, I will give their explanation 

 below, from above downwards : — 



Portlandien, — Portland Rock. 



Kimmeridgien, — Kimmeridge Clay. 



CoralHen, — Coral Rag. 



Oxfordien, — Oxford Clay. 



Callovien, — Kelloway Rock. 



Bathonien, — Bath Oolite. 



Bajocien, — Lower Oolite, from Bajocea or Bayeux in Calvados. 



Toarcien, — Upper Lias, from Toarsium, or Thouars. 



Liasien, — Middle Lias, or Marlstone. 



Sinemurien, — Lower Lias, from Sinemurium, or Semur. 



In respect to this nomenclature, I may observe, that in common 

 with every other, it possesses the disadvantages necessarily attendant 

 upon every attempt at the classification of still imperfect materials. 

 Eight of the names are derived from local deposits, and are, therefore, 

 useful as indications of supposed typical localities ; but this advantage 

 has the counteracting disadvantage of leading observers to anticipate 

 a much greater identity in the faunae of different localities than our 

 present knowledge will allow us to expect : one is founded on the 

 predominance of a special order of fossils, but here again the geo- 

 logist would be led astray, were he to seek for or expect to 

 find a similar fauna at each equivalent epoch in the formations of 

 every portion of the globe. The great question really is, what 

 deposits were in course of formation in France or Germany, or in 

 any other portion of the world, at the moment when the Oxford 

 Clay and the Kimmeridge Clay were being deposited in England, or 

 when corals were abounding on its shores ? Such names, therefore, 

 should be considered as merely significant of the port, as it were, 

 from which the geologist intends to commence his voyage of dis- 

 covery. 



Perhaps no epoch in the history of the world is so deserving of 

 consideration and reflection as that in which the Tertiary strata have 

 been deposited, as the relics of species imbedded in them, which 

 have continued to exist up to our own time, must at least dispel 

 from our minds the idea that any vast destructive agency destined 

 to annihilate one creation as a preparation for another could have 

 operated on the fauna within this period. The vast extension of 

 these formations, once considered merely local deposits, is also a fact 

 deserving of attention, though in itself so natural. The research 



