144 



Coal Measures, as differentiated from the overlying Wind- 

 sor series. More recently, field geologists, especially 

 Fletcher and Ells on structural and stratigraphic grounds, 

 assigned much of Dawson's Carboniferous, including the 

 Horton, to the Devonian. This reference gave rise to a 

 discussion, not yet settled, which involves not only this 

 series but the Riversdale and Union formations of Nova 

 Scotia as well, and also the fern beds of St. John, New 

 Brunswick. An interesting synopsis of the controversy 

 was published by Fletcher in 1900 [12]. 



In later years the plants of these beds were submitted to 

 Kidston of England and to David White of the U. S. 

 Geological Survey, these two paleobotanists gave inde- 

 pendent confirmation of the age of the Horton, Kidston 

 [13] considering it was undoubtedly Lower Carboniferous, 

 while White [14] stated that " the Horton plant terrane 

 should, on purely paleobotanical grounds lie below the 

 typical Carboniferous Limestone [Windsor series]; but I 

 believe it should go hardly so low as the Ursa stage [upper- 

 most Devonian], or below the boundary generally accepted 

 for the Lower Carboniferous [Mississippian]". In com- 

 parison with the Mississippian beds of Pennsylvania 

 and Virginia, Mr. White would place the Horton as nearly 

 synchronous with the Pocono (Kinderhook). He also 

 regarded it as the near equivalent of the Albert shales 

 of New Brunswick and of the Calciferous Sandstone series 

 of Scotland. A. Smith Woodward [15] has likewise 

 pronounced on the Carboniferous age of the Horton fish 

 remains, and finally L. M. Lambe, [16] who described the 

 fauna of the Albert shales, has correlated these two 

 series as quite, or nearly synchronous, and equivalent to 

 the Calciferous Sandstone series as developed in Mid- 

 and West Lothian and elsewhere in Scotland. 



the horton flora. 



(David White.) 



The Horton flora, like its probable contemporaries at 

 the base of the Carboniferous in the Arctic regions of 

 Alaska, Bear island, and Spitzbergen, and in Siberia, as 

 well as in the Appalachian trough, is remarkable at once 

 for its paucity in genera and species and for the great 

 profusion of two or three very variable dominant plants. 

 The fern-like plants, which probably are Cycadofilic, vary 



