SO PHILOSOPHICAL TRANSACTIONS. [ANNO 17Q6. 



face, and that some of these poles are more powerful in their action than others, 

 from the variation observed in various places of the globe. 



XIV. Discovery of some very Singular Balls of Stone, found in the Works of tTie 

 Huddersfield Canal. By Mr. Benj. Outram, Engineer, p. 350. 



The Huddersfield canal is to be carried through that chain of mountains which 

 extends from the Peak of Derbyshire, in a northward direction through Yorkshire, 

 &c. into and through a great part of Scotland, by pursuing from the navigation at 

 Huddersfield a deep and narrow valley to Marsden, where it enters the north- 

 eastern foot of one of these mountains, called Pule Hill, under which it is to be 

 extended south-westwardly by a subterraneous cut or tunnel to the foot of Stand 

 Edge Hill, or Brunn Clough, where it again excavates ; and pursuing the bottom 

 of a deep valley into Saddleworth, passes along the banks of the Tame to Ashton- 

 under-Lyne, where it joins the canals that extend to Manchester, Stockport, Peak 

 Forest, &c. 



In the latter end of the year 1794, the miners employed by the canal company 

 began to perforate the north-eastern foot at Pule Hill : the strata they first cut 

 through consisted of a greyish coloured shale, the beds or laminae of which did not 

 lie quite horizontal, but dipped or declined a little to the westward. The strata 

 continued regular till the workmen had perforated about 240 yards in length 

 from the entrance of the hill, and were about 80 yards deep from the surface of the 

 ground immediately over them, when they discovered on the north side of their work 

 a fault, throw, or break of the strata, which was filled with shale, reared on the edge, 

 and mixed with softer earth, and in some places with small lumps of coal. In con- 

 tinuing to pursue the direction of the tunnel, this fault occupied by degrees more of the 

 space of the tunnel, for about 40 yards in length, when it nearly occupied the whole 

 tunnel, which is near 4 yards in width': and at about 5 feet from its southern mar- 

 gin it contained a rib of lime-stone, near 4 feet thick in the bottom, but not quite 

 so thick at the top of the tunnel ; and on each side of this rib it contained balls of 

 lime-stone promiscuously scattered, and of various sizes, from 1 ounce to upwards 

 of 100 lbs. weight. 



The rib and balls of lime-stone were first found at about 280 yards from the 

 north-eastwardly end of the tunnel, where it is about 90 yards in perpendicular 

 depth from the surface ; and the workmen have now pursued the tunnel to near 

 350 yards from the entrance, and the rib of lime-stone and balls continue nearly 

 the same ; the rib has varied a little in thickness, and has not pursued a straight 

 line ; in one place it nearly left the tunnel to the northward, but in a few yards 

 turned southward, to its former direction. The lime-stone of the rib is not per- 

 fectly pure, that in the balls is still less so, but it makes a good lime for cement. 

 The balls when broken appear to be mixed with a kind of pyrites, in small particles, 

 near their outward edges ; their form is very peculiar, being similar in all their 



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