DEVONIAN. 329 



series 3, 4, 5, or even above them; more evidence will be needed to determine their position 

 with certainty. 



The Chapman sandstone fauna is younger than the Square Lake fauna; the present opinion 

 is that it corresponds closely with the Lower Oriskany of the New York and interior series. 

 The identification of the fauna with Honeyman's zone D Arisaig and with the "Tilestone" 

 fauna of Wales establishes its place at the top of the Silurian. (See Am. Jour. Sci., 4th ser., 

 vol. 9, p. 203.) 



The Moose River fauna is a facies of the Eodevonian and represents the Oriskany. 



The Mapleton sandstone is the representative of the higher parts of the Gaspe sandstone, 

 and is the Old Red sandstone facies not expressed in New York until a point higher up, in the 

 Catskill sandstone, is reached. 



Besides these terranes, determinable by their fossils, there are slates and crystalhne rocks, 

 the precise age of which is undetermined. The slates are presumably Cambrian or pre-Cambrian. 



L 20. NOVA SCOTIA. 



The supposed Devonian rocks of Nova Scotia were described in 1886 and 1890- 

 91 by Fletcher, ^^*'''^^^° who distinguished a "lower conglomerate group," a "middle 

 gray sandstone and slate group," and an "upper red slate and sandstone group." 



In his second report Fletcher gave the following general account : 



Most of the metamorphic areas of the hiUs of Antigonish, Pictou, and Colchester counties 

 consist of rocks whose geological position is between the group containing marine fossils of Lower 

 Helderberg age, and the Carboniferous or Mountain limestone, also characterized by the occur- 

 rence of marine types, whereas all the fossils found in the intervening Devonian consist of shells 

 indicative of shallow-water origin, and of plants both drifted and erect, indicating land condi- 

 tions. Between this series and those underlying and overlying, there is everywhere the clearest 

 evidence of enormous unconformity, and although from the abundance of their plant remains 

 they have sometimes been confounded with Millstone grit and even higher strata, their rela- 

 tions to the Carboniferous limestone at the East Mountain of Onslow and Penny's Mountain, at 

 Shubenacadie, Stewiacke, Walton, Cheverie, Parrsboro, and wherever the two series are in 

 contact, and the ease with which they can be traced from point to point, show that they are to 

 be compared rather with the Mispeck and Little River groups of New Brunswick, and that the 

 Carboniferous limestone rests unconformably on the slates. 



In spite of their disturbed and partly altered condition, these rocks have yielded 

 fossils, which show that a considerable part of the supposed Devonian contains a 

 middle Carboniferous fauna and flora. The stratigraphic evidence of Devonian 

 age has been controverted by the paleontologic evidence of Carboniferous age. 

 Ami ^^ has recently summed up the results of investigations covering both lines of 

 evidence as follows : 



For many years it was taken for granted t"hat the highly fossUiferous beds of carbonaceous 

 shales, etc., known as "the fern ledges" of New Brunswick, were of Devonian age, although the 

 character of the flora, even at first sight, is one of decidedly Carboniferous facies. The 80 or 

 more species representing the flora of that period are preeminently Carboniferous, and recently 

 Mr. David White has recorded no less than 17 species of Pottsville forms, which came originally 

 from the "fern ledges." The Lancaster formation of the author was defined as that series 

 of strata which held this very characteris jic flora, and it is capped by another Carboniferous 

 formation consisting of red shales and conglomerates, with but few species occurring therein; 

 to which formation the designation Mispeck formation of New Brunswick was applied. These 

 two formations, the Lancaster and the Mispeck, find their equivalents in the Union and Rivers- 

 dale of Nova Scotia, which Sir William Dawson always held to be of Middle Carboniferous age 

 (Middlestone grit) . 



