28 EDWIN GILPIN ON THE FAULTS AND 



of granite, all intervening between the Atlantic and the Carboniferous lying to the north, 

 and along the gulf of St. Lawrence, and also underlying them, dill'erent results would 

 appear. The more plastic and regular strata would be subjected to the movements of a 

 comparatively rigid body. Therefore, in addition to the general east and west folds, there 

 are met transverse flexures and local undulations, which can in some cases be referred to 

 projecting ridges of the older strata, or to their undulations extending under the carboni- 

 ferous. 



In the case of the Pictou coal field, as the folding proceeded, it was limited by the 

 outlines of the subjacent and boundary rocks older in age ; and the more yielding measures, 

 the Carboniferous, were bent and fractured according to the varied position of these outlines. 

 The longer the folding continued, the more marked the fracture, which resulted in each 

 underlying ridge of older measures coming finally into contract with the upper beds of 

 the productive strata. 



Thus the coal measures at one point in the south side come directly against McLellan's 

 Mountain, and similarily on the north side against Waters Hill, both Pre-Carboniferous 

 ridges. "While at either end of these once hidden hill tops, the prolongation of the 

 fractiires along the foldings merely bring the various Carboniferous horizons into 

 unconformability. Similar examples of this are seen at Mabou, and Cape Dauphin, in Cape 

 Breton, where the Pre-Cambrian come into close relationship with the coal measures, 

 while a short distance away, the foldings and the faults of elevation intermix only the 

 carboniferous subdivisions. 



In the Pictou district there are, as has been already mentioned, transverse foldings. 

 It may be noticed that when the east and west foldings had attained approximately their 

 present attitude, and when by degrees the tension had been relieved by the succession of 

 faultings which are now practically represented as a fault bounding the coal field on the 

 south as well as on the north, the subordinate transverse foldings would arise from a 

 further continuance of the movement. Then the more prominent spurs and ridges of the 

 Pre-Carboniferous would inflict, on the superimposed strata, elevations giving rise to subor- 

 dinate transverse folds. Thus in this district the points of maximum elevation of these 

 foldings are found opposite the Pre-Carboniferous of McLellan's and Waters Hills. 



The south and north edges, therefore, of the Pictou main synclinal, are marked by 

 the series of faultings which bring lower measures up abreast of the productive ; the 

 continuation of the movement produced, along the line of deep buried ridges or spurs, 

 transverse foldings which made their mark when the once great and solid mass of 

 sediments had been divided into longitudinal masses. 



The practical application of these principles to the business of the miner becomes 

 evident when it is considered that almost all faults result from foldings such as the 

 Pictou district exhibits in a typical form. The east and west faults are those connected 

 directly with the main foldings, while those running transversely are caused by the 

 subordinate elevations, or are the resultant of the variations of the main folds from straight 

 lines, owing to spurs of the older rocks projecting under the Carboniferous. 



Thus in the western district, the main synclinal axis dips eastwardly until a point is 

 reached about a mile west of the East River ; here it reverses and dips to the west, forming 

 what is turned by the miners a " saddle." The coal has been worked extensively near the 

 line of the axis, and there are met, at intervals of from five to twenty chains, " up-throws," 



