QUARTERLY JOURiNAL 



THE GEOLOGICAL SOCIETY OF LONDON. 



PHOCEEDINGS 



OF 



THE GEOLOGICAL SOCIETY. 



Pebrxjaet 21, 1872. 



Frank X. Wardell, Esq., of Sandal House, Wakefield, Yorkshire, 

 one of H.M. Inspectors of Coal Mines, and Mortimer Evans, Esq., 

 C.E., of West Eegent Street, Glasgow, and Skelmorlie Heights, 

 Wemyss Bay, Ayrshire, were elected Fellows of the Society. 



The following communication was read : — 



MiGEATioisrs of the Graptolites. Bv H. Alleyne Nicholsokt, M.D., 

 D.Sc, M.A., Ph.D., F.R.S.E., F.gIs., Professor of liatural History 

 and Botany in University College, Toronto. 



Most geologists are now prepared to admit that the occurrence of 

 the same species of marine animals in strata very widelj" removed 

 from one another in point of distance may he accepted as a proof of 

 " migration " having taken place. It does not matter, from this 

 point of view, whether the deposits of the two areas are approxi- 

 mately of the same age, or whether they succeed one another in 

 point of time — except that in the former instance we can hardly 

 ever he sure which of the areas has heen peopled from the other. 

 It follows also from this view that strata containing exactly the 

 same species of fossils, if very widely separated in point of distance, 

 can never be exactly " contemporaneous." They may have heen 

 formed nearlj^ at the same time, and they will belong to the sam-e 

 geological epoch ; but the one must really succeed the other in 

 point of time. It will be understood, of course, that this statement 

 is only intended to apply to cases in which identical fossils are found 



VOL, XXVIir. — PART I. R 



