396 NORTHERN OUTCROP, CUMBERLAND COAL FIELDS — GILPIN. 



remain practically unaltered, be reasonable ground for expecting 

 to find the different seams better adapted for the miner's work 

 than at the Joggins. 



I have already spoken of the Ragged Reef sandstones forming 

 the upper cover of the Productive Measures. This sandstone, 

 occurring in massive beds, overlaid by red and gray shales and 

 sandstones, has been traeed into the eastern district. From the re- 

 port of Mr. McOuat, already quoted, it appears that it crosses the 

 Maccan River below Athol, and strikes the Little Forks River 

 about a mile below the Styles Brook, and follows the course of 

 the river to a point about a mile beyond the post road. 



The vertical thickness of Productive Measures between the base 

 of this sandstone and the Millstone Grit is, at the Joggins, 4757 

 feet ; at the Styles Brook, 4500 feet, equivalent at the latter 

 place to an interval of about a mile, measured horizontally. From 

 the course of the conglomerate, which turns to the south about 

 three miles beyond the Styles mine, it would at no great distance 

 run under the sandstone. This is accounted for by the officers 

 of the Survey on the supposition of a great fault, an upthrow to 

 the east, probably of several thousand feet. There are other me- 

 thods by which this apparent obliteration of the Productive 

 Measures can be explained, but the discussion would make this 

 paper too long. 



This district affords a capital illustration of the principle that 

 Nature never yields her secrets to the efforts of individuals con- 

 fined to limited districts. Explorations had been carried on for 

 years in ignorance of the fact that to the north of the Productive 

 Measures the line of the Millstone Grit had been drawn clearly 

 and distinctly ; and that to the south an equally distinct barrier 

 defined the area in which the prospector would legitimately exer- 

 cise his skill and perseverance. 



The work of the Geological Survey in this coal field, for some 

 unexplained reason, was left incomplete, but so far as it has been 

 carried in the Northern district, useful hints have been given to 

 the prospector, which I have endeavored to place plainly be- 

 fore you. 



We have seen that at the Joggins, the workable seams and the 



