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 Jater- 
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 aud 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 Calamites, Sphenopteris, Anthracomya elongata 
and A. laevis, Lepidodendron corrugatum, Stigmaria ficorides, 
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. 
