INTRODUCTION. XXXI 



equivalents, because it is believed "that much more extensive 

 studies of these formations ought to be made before any such 

 correlation can be satisfactorily established." 1 



Referring to Newberry's discovery of Potomac species in the 

 Kootanie beds of the Great Falls of Missouri river in Montana, 

 White points out that, although some of the plants may be 

 identical, it is certain the waters in which the two formations 

 were deposited were geographically widely separated. 2 



CANADA. 



In a table of correlation given by Newberry 3 in a paper on the 

 Cretaceous floras of North America, he places the Kootanie plant- 

 bearing beds of Canada on the same horizon with the European 

 "Wealden. Dawson 4 considers these beds as representatives of the 

 Urgonian or Neocomian series; he compares them to the Kome 

 beds of Greenland. There are, however, no typical Wealden 

 plants included in Dawson's list ; a comparison is made between 

 Salisburia (Ginkgo} lepida, Heer, and certain leaves described by 

 Dunker from the Deister Wealden, but no reference is given to 

 indicate what particular leaves are referred to. The only plant- 

 beds of America with which Dawson compares the Kootanie fossils 

 are some in Maryland, in which Tyson discovered large Cycadean 

 stems and which he referred to a Wealden age. 5 



JAPAN. 



In 1877 Geyler 6 described and figured twelve species of 

 "Jurassic" plants from the valley of the Tetorigawa in Kaga, 



1 Bull. U.S. Geol. Surv. No. 82, p. 208. 



2 Ibid. p. 252. 



8 Trans. N. York. Ac. Sci. vol. v. 1885-86, p. 135. 



* Trans. E. Soc. Canada, vol. iii. 1885. 



6 Ibid. p. 18. 



6 Palaeontographica, vol. xxiv. p. 221. 



