AN" AFTERNOON WITH THE OVENDEN NATURALISTS. 



THE NEW RAILWAY FROM HALIFAX TO BRADFORD. 



By James Spencer. 



An excursion over the line of the new tunnel now making under 

 Queensbury, from Netherton to Hole Bottom, on the Clayton side of 

 the hill, yielded us some interesting facts. The great 52 yards fault 

 at Netherton Bridge is followed, a little further on, by an anticlinal 

 axis, where the grit rocks are seen to bend over on either hand. The 

 entrance to the tunnel on this side is being excavated in the rough 

 rock, which is here very hard and massive. It is overlaid by the seat 

 earth and bed of coal which accompany this rock, wherever it has a 

 good covering of shale, throughout its entire course from the 

 North of England to the Midland Counties. The coal reaches 

 two feet in thickness in some places in Lancashire, but in this 

 district, and throughout a great part of its range, it is only about 

 six inches. 



In the debris from No. 2 shaft we found that well-known mineral, 

 cone-in cone." It occurs in the strata between the Hard and Soft 

 bed coals, and appears to have an extensive range, being found also 

 in Shibden Dale, Southowram, and Elland. 



It varies in thickness from one to six inches, but occasionally I have 

 found it a foot or more in thickness. It is composed of a great 

 number of cones fitting into each other, hence its name, cone-in-cone." 

 It almost invariably (in carboniferous rocks) occurs in connection with 

 a layer of clay-ironstone, which generally underlies it. It has long 

 been a disputed point as to whether it was of mineral or of vegetable 

 origin ; but its mineral characters are clearly shewn in some beautiful 

 microscopic sections which I have in my possession. It appears to be a 

 peculiar form of crystallization, occurring in beds overlying clay-iron- 

 stone in most of our coal fields. In the great South Wales coal-fields 

 it is said to occur in connection with nearly every bed of iron ore. 

 The same form of crystallization occurs in connection with other 

 minerals, and is more extensively diff'used in the earth's crust than was 

 formerly imagined. In this neighbourhood I have found it in the 

 Yoredale rocks of Hebden Bridge, in the Millstone-grit rocks, where it 

 occurs in two beds, one in the shale upon the Kinder-grit, and the 



