GKXERAL LAWS OF ORIGIN AXD MtGRATIOX. 239 



Bet\nvn 1800 and ISTO the writer \v;is engaged in 

 workiojf out all tluU could bo learniHi of the Devonian 

 phuits of eastoni .Vmerica, the oldest known flora of any 

 richness, and which cfMisist-;; almost exclusively of gigantic, 

 and tv^ us givtesque, representatives of the clnb^mosses, 

 ferns, and nian^s'-tails, with some tivt^i! allied to the cycads 

 and pines. In this pnrsuit nearly all the moix^ important 

 localities werv^ Yisited, and iunvss was had to the large 

 collections of Prof. Hall and Prof. Newberry, in New 

 York and Ohio, and to those made in the remarkable 

 plant-bearing beds of Xew Brunswick by Messrs, Matthew 

 and Ilartt. In the pivgivss of these researches, which 

 develojMHl an unexpectedly rich assemblage of species, the 

 northern origin of this old flora seemed to be established 

 by its earlier culmination in the northeast, in connection 

 with the growth of the American land to the southward, 

 which took place after the great Upjn^ Silurian subsi- 

 dence, by elevations beginniuir in the north while those 

 portions of the eimtineut to the southwest still remained 

 under Uie sea. The same result was indicated by the 

 persistence in the Oarboniferons of the south and west of 

 old £riaa forms, like M(>galopteri)!. 



When, in 1S70, the labours of those ten years were 

 brv^nght lK>for>.> the Royal Society of London, in the 

 Bakerian lecture of tliat year, and in a memoir illustrat- 

 ing no less than one hundred and twenty-fire species of 

 plants older than the gn.\it Carboniferous s\-stem. these 

 diHlnctions wv>re statt^d in ctunneotion with the conclusions 

 of Hall, Logan, and Dana, as to the distribution of soili- 

 ment along the northeast side of the American continent, 

 and the anticijiation was hazarded that the oldest Palseo- 

 soic floras would be discovenMi to the north of Newfound- 

 land. Mention was also made of the apjwrent earlier 

 and more copious birth of the Devonian flora in America 

 than in Europe, a feet which is itst^lf connected with the 

 greater north warvi extension of this continent. 



