236 GEOLOGICAL NOMENCLATURE 



It was subsequently found that the large Pre-carboniferous 

 area, eighteen miles wide at the Strait of Canso and five miles 

 in width at Lochaber, thirty-five miles to the south-west, instead 

 of being Silurian as claimed by Sir William Dawson, contains 

 only these plant-bearing Devonian strata which are divisible 

 into three groups corresponding closely with those into which 

 the Devonian rocks of New Brunswick had already been sub- 

 divided. They extend from Lochaber along the East River of 

 St. Mary's and the East River of Pictou to strike the Inter- 

 colonial railway near Glengarry, form the high land south of 

 Truro and pass unconformably beneath the Carboniferous of 

 Stewiacke River; and a small area is found at MacAra Brook, 

 from which come the fish remains and Pterygotus subsequently 

 described by A. Smith Woodward as homotaxial with the upper 

 Silurian or lower Devonian of England. 



As this grouping affected also rocks referred by Sir William 

 Dawson * on the evidence of their fossil plants " to the lower 

 part of the coal formation or Millstone Grit " and even higher, 

 it was naturally called in question; and in 1885 Mr. T. C. 

 Weston was sent to Nova Scotia, assisted by Mr. J. A. Robert, 

 to collect fossils between Riversdale and the Strait of Canso. 

 They found everywhere Lepidodendron corrugatum, Stigmaria 

 ficoides and Cyclopteris acadica, forms supposed to be charac- 

 teristic of the Horton series ; on the East River of St. Mary's 

 plants which resemble rhizomes of Psilophyton ; and, near 

 Sunnybrae, Cordaites and numerous markings of Psilophyton 

 allied to P. glabrum and P. elegans ; at and near Riversdale 

 they obtained Catamites, Sphenopteris, Anthracomya elongata 

 and A. laevis, Lepidodendron corruyatum, Stigmaria ficoides, 

 ferns and erect trees, characteristic again of the Horton series. 



These rocks near Truro and on Cobequid Bay and Minas 

 Basin had in the meantime been recognized by Dr. Ells as 

 probably identical with the Devonian of New Brunswick. 



* Acadian Geology, pages 485 and 489; Plants of the Lower Carboniferous and 

 Millstone Grit, p. 13. 



