WHE CARBONIFEROUS OF CAPE BRETON— GILPIN. 291 
is that of valleys between the ridges of the older rocks, and 
their softer strata have been worn into broad river valleys and 
rolling hills of inconsiderable altitude. When they rest on the 
flanks of the pre-carboniferous hills they present charming and 
picturesque gorges worn by the brooks which are long nourished 
by the accumulated winter snows. 
The Eastern or Sydney district presents unusually fine natural 
sections, and has received much attention owing to the extensive 
inining operations which have been carried on during the past 
century. Its structure has been carefully worked out, and as it 
is a typically well developed carboniferous district a brief des- 
cription of the various subdivisions will serve in great measure 
as a guide to these in other parts of the island. 
In the Sydney or Eastern district the following subdivisions 
are recognised :— 
Productive Coal Measures. 
Millstone Grit. 
Marine Limestone Formation. 
Lower or Basal Coal Measures. 
The upper subdivision, that of the upper Coal Measures, being 
absent, unless represented by the beds at Low Point, overlying 
the Carr Seam. 
The shore from Cape Dauphin to Mira Bay is occupied by the 
productive measures, which are folded in three undulations hav- 
ing a general Kast and West course. As the measures are inter- 
rupted at the anticlinals the exact identification of the seams 
has not been made out. 
The following section, taken in the Lingan district, will serve 
to show the thickness and relative positions of the best known 
seams :— 
Strata and Coal. 
Seam, ft. in. 
SenmuA xs. sad. Ree ORLO I Als 3 
‘ ee ec BE Risiee, RHEL Rar inh 306 : 
CaP NS. LA : pC tae BGA? 6 5 
OS alae hte pie Sea Tete Sg SogTR ANS 190 af 
Barrasois, Hub or Block House ......... 12 1 
= tA cna oe SA tselal STO 3 
