140 EDWIN GILPIN ON THE FOLDING OF THE 
succeeding the Carboniferous limestone at the Joggins, where they attain a thickness of 
6,000 feet. They extend to the eastward, and succeed the same measures in Pictou County 
with equal regularity, and have a thickness of 5,373 feet, according to Sir William Logan’s 
Survey. They appear to thin out to the eastward, and are represented in Antigonishe 
County by beds of coarse sandstone underlying the Hollywell coal, and possibly by the 
measures holding the Tracadie coal beds, which appear to succeed the Carboniferous lime 
stone. In the Bay of Fundy District they are represented by a great mass of sandstones, 
and hold coal beds possibly belonging to the lower part of the productive measures. 
In Richmond County their extent and position is not as clearly defined as elsewhere, 
and from Mr. Fletcher’s report (Geological Survey), they appear to be 5,500 feet thick. 
Passing to the eastward, they are found at Salmon River and Mira, overlapping, with marks 
of unconformability, the Carboniferous limestone, and join the same horizon in the Sydney 
district. Here their maximum thickness is 5,700 feet, diminishing to 500 feet at Cape 
Dauphin. At several points in this district they contain fragments of the Carboniferous 
limestone series, already alluded to as having been folded. Their passage into the produc- 
tive measures is here an arbitrary line. In Newfoundland they succeed regularly to the 
carboniferous limestone, and have a thickness of 2,000 feet. - 
We have, therefore, two lines of maximum depression, one passing through the 
Joggins, having on each side of it, at Hillsboro and the Basin of Minas, areas of lessened 
depression. Another point of maximum depression is in the Richmond district, dimin- 
ishing toward Pictou, and toward Salmon River, and increasing again in the Sydney 
district. The corresponding area of lessened deposition is shown by the decrease of 
thickness to the north of the Sydney district. 
The general conditions of deposition may be justly regarded as having been somewhat 
more rapid than those which accumulated the productive measures, but there are excep- 
tions to this rule. We find beds of coal at the summit of the Millstone Grit in Newfound- 
land and Cape Breton, possibly also at Tracadie, at the French and West Rivers at Pictou, 
and in the Colchester district. These may mark periods of subsidence of a more gradual 
nature than those generally occurring in the district under consideration. So far as I can 
learn, these intervals are not confined to any particular horizon in the Millstone Grit. 
These measures appear to have undergone very little violent movement at this time, 
except in the Pictou district, where they were indurated, folded and elevated. This was 
followed by a rapid subsidence, permitting the formation from their ruins of an immense 
mass, known as the New Glasgow Conglomerate, which attains a maximum thickness of 
1,600 feet. These Conglomerates, as shown by Dr. Dawson, represent the close of the Mill- 
stone Grit, which, in the New Glasgow district, does not appear in direct conformability 
with the productive strata of the Middle Coal formation, owing partly to the faults bound- 
ing the coal field, as well as to the movements chronicled by the Conglomerate. 
PRODUCTIVE Coan MEASURES. 
Passing over the New Brunswick district we meet these measures at the Joggins, suc- 
ceeding regularly to the Millstone Grit, and having a thickness of 4,673 feet. They can be 
traced for twenty miles to the eastward, where they are apparently overlapped by the 
Upper Coal formation. They presumably extend under these measures, and connect with 

