270 MR MILNE ON THE MID-LOTHIAN AND EAST-LOTHIAN COAL-FIELDS. 



lar balls. At Dryden, there is a band in the lower series of coals (between the 

 glass and the stoney coal), 14 inches thick, which 3delds about 33 per cent, of iron. 

 It is understood that there is a still thicker band there, near the south parrot coal. 

 Whether or not this band runs, like the coals, throughout a great extent of country, 

 has not yet been ascertained. I have seen, in a bed of shale, thin seams of 

 black band, continuous for a few hundred yards, and then entirely cease. 



The clay-ironstone of the district appears to occui' most frequently in the 

 form of balls or irregular lumps. It is a remarkable circumstance that eveiy one 

 of these is found to contain more or less organic matter. At Wardie they con- 

 tain the scales, teeth, coprolites, and other remains of fish.* At Cowpits and 

 Pinkie Burn, they contain large quantities of bivalve shells resembling a Unio. 

 There are apparently two species among the shells in my possession, — one of them 

 much more elongated than the other. The last has the round and tumid shape 

 of the species noticed in Dr Hibbert's paper as having been found at Burdie- 

 house ; but all the specimens I have seen from Cowpits are of a lai-ger size than 

 the Burdiehouse shell. The nodules containing these bivalves, are imbedded in 

 a stratum of shale about 2 feet thick, which forms the roof of a coal caUed the 

 " three feet coal." The stratum immediately above the shale is whitish sand- 

 stone, about 30 feet in thickness ; and above the sandstone is a bed of shale, 

 which forms the pavement of the Bar's coal. This muscle-band (as it is termed) 

 was seen not only at the two places just mentioned, but also at Midfield engine, 

 so that it covered a district in one direction of about three miles. There are strong 

 reasons for thinking that the same muscle-band runs south to Smeaton, and 

 that it also appears on the west side of the basin, at Jojypa (on the shore), at 

 Easter Duddingston old engine-pit, at Wanton Walls deep level, and near Somer- 

 side ; f so that it now covers between tAventy and thirty square miles of horizontal 

 surface. 



VII. The next subject connected with the stratified rocks of the district; is 

 the sUps or fissures which traverse them. The fissures now referred to are very 

 different from those previously described, — which concerned merely the inter- 

 nal structure of individual strata. Those now to be described, traverse aU the 

 strata of a particular district, for many hundred yards or even for miles, and reach 

 to a depth which has never been ascertained. 



These fissures (known to the colliers under the various names of hitches, 

 faults, dykes, troubles, slips) show that the strata they intersect have been broken 

 across; and that they have thereafter, on one or both sides of the fracture, 

 changed in their position, so that the fractured ends of the strata are no longer 



* For an analysis of this ironstone, see Appendix C. 



t All these places, except the first, ai'e stated on the authority of Farey. 



