loo The Ottawa Naturalist. [July 



ing" species, Whitilescya Dawsoniana, whose description, through 

 the courtesy of Professor Penhallow of the University, I am 

 enabled to include in this paper. The '^' fern ledges " have been, 

 and are still, regarded by most Canadian geologists as Middle 

 Devonian. ^ The composition of this flora is essentially that of 

 the Pottsville of the Allegheny region, to which most of the Lan- 

 caster ferns are common. In fact, the fossil flora of the " fern 

 ledges" appears to be representative of the Pottsville (Millstone 

 Grit in part) of the United States. The more exact distribution 

 of the species seems clearly to indicate, as I have elsewhere re- 

 marked,- the reference of a portion at least of the *' fern ledges" 

 to the Upper or Sewanee division of the Pottsville. 



The discovery oi Whittleuya at once in the Riversdale of 

 Nova Scotia and in the Lancaster formation of New Brunswick 

 not only tends to confirm the conclusion as to the approximate 

 contemporaneity of these formations, a relation that has long been 

 accepted by most geologists, with the exception of the late Sir 

 William Dawson, but it is also corroborative of the correlation of 

 both of these formations with the Pottsville.^ 



^ Sir William Dawson, Fossil Plants of the Devonian and Upper Silurian 

 formations of Canada; Gaol. Surv. Canada, 1871. L. W. Bailey, Observa- 

 tions on the Geology of Southern New Brunswick, 1S65, pp. 54-76. Hugh 

 Fletcher, Geological Nomenclature in Nova Scotia, Trans. Nova Scotia Inst. 

 Sci., vol. X, 1900, p. 235. 



2 20th Ann. Rept. U. S. Geol. Survey, Pt 2, 1900, p. 917. 



^ The Pottsville ("Pottsville conglomerate") in the type section in the 

 Southern Anthracite field of Eastern Pennsylvania covers the interval, including 

 a basal transition, between the marine Lower Carboniferous and the Lower 

 Productive Coal Measures. Its lower portion contains a flora apparently 

 corresponding to the Ostrau-Waldenberg zone of Europe, included by many 

 palaeontologists within the top of the Lower Carboniferous. The upper 

 portion includes the plants of the Millstone Grit and of the Lower Coal 

 Measures of the Old World. Mr. Kidston's reference of the St. John Flora to 

 the Lower Coal Measures corresponds perhaps exactly to my correlation of 

 the plant beds with the upper portion of the Pottsville, since, as he has pointed 

 out (Proc. Roy. Phys. Soc. Edinburgh, vol. XII, 1S94, p. 225), the Millstone 

 Grit flora of Europe is essentially the same as that of the Lower Coal Measures, 

 from which in many cases the Millstone Grit seems not to have been entirely 

 stratigraphically distinguished. 



