78 
many sailors have vouched, and whose testimony has been endorsed 
by a recent essayist before this Society, be “ the last of the 
Mohicans,” handing down the tradition of these Lnaliosaurian 
monsters to our own times. In like manner among the mollusca, 
Ave have no living representatives of the numerous Ammonites, 
Tnrrilites, Bacnlites, and other Cephalopoda which Avere character- 
istic fossils of the Secondary rocks. And yet these Eocene strata 
rest directly on the Chalk, Avithout any transition beds Avhatever, 
and there is nothing in the Avhole Avorld Avith which Ave are at 
present acquainted, to supply this missing link in the geological 
history. 
There is no reason Avhatever to suppose that these changes from 
sea to laud, from tropical to arctic climate, from the Palms and 
Cocoa-nuts, Turtles and Crocodiles of the London Claj'', to the 
Elephants and Pines of the Forest-bed, took place suddenly. On 
the contrary, no scientific vicAvs have been, during recent years, 
more firmly established, than those of the Uniformitarian school, 
Avhich teaches that these transformations, in the organic as in the 
inorganic Avorld, have been brought about by the sIoav and gradual 
operation of causes similar, and probably of no greater intensity, 
than those Avith Avhich Ave are ourselves familiar. As far as the 
inorganic Avoiid is concerned, no one hears noAv of the catastrophes 
and cataclysms Avhich Avere formerly part of the regular stock-in-trade 
of geologists, and I think the most careless reader of scientific 
literature must have observed, as to the organic Avorld, that the 
discussion as to Avhether or not evolution is true, has altogether 
ceased, the only question now being in Avhat direction it has 
proceeded. 
