272 



THE GEOLOGIST. 



with these ore-caverns, which are locally termed *' churns, ' there 

 are some facts deserving special notice. Directly beneath the lowermost 

 bed of the stratified rock, termed by the miners the ''lidstone," the 

 "crease" is traversed by a series of irregular joints or pipes, technically 

 termed "leads," which rise out of the "churns," and often penetrate 

 into the " lidstone," and even far beyond into the overlying rocks, 

 coming out to the day. These "leads," when followed, usually 

 increase in width, and then expand at the depth of a few feet — perhaps 

 of only a few inches — into the churn-proper. The churns are not isolated 

 pockets, but have strings or branches, more or less numerous, likewise 

 termed " leads," which communicate with other churns lying either in 

 the same plane, or in an inferior or superior one ; hence the search for the 

 ore is not of that precarious nature that it would have been had the 

 "churns" been solitary, and not connected deposits. Experience has 

 proved that the smaller the lead the larger generally is the " churn." 

 The growth of the " mine-ground," to use a miner's expression, or the 

 mode in which the ore is dispersed in the " churns," much resembles 

 the conditions under which crystallized deposits of other minerals, 

 Buch as carbonate of lime and sulphate of barytes, are often found 

 in other caverns. The roofs of those churns which lie nearest to the 

 lidstone are invariably encrusted with stalactitic ore, the crystallization 

 apparently radiating towards the centre of the segments of the circles 

 which are described by the irregular rolling form of the roof. In 

 the dividing masses of "crease," geodes are exceedingly common, and 

 concretions of compact haematite, lined with shining crystals of hydrous 

 oxide of iron, are constantly detached from near the walls of the 

 churns ; the interior of the large churns, however, are mostly filled 

 with powdery red haematite, held together by a slender frame- work of 

 crystallized or compact ore, which trills easily before the pick, ren- 

 dering the getting very inexpensive. In manj- of the old workings 

 large quantities of the powdery ore or "Smith's Mine," which forms 

 by far the richest product of the churns, have been found from time to 

 time, having evidently been rejected by the old miners, who were pro- 

 bably unable to use it from its choking the furnace in the air bloomeries. 

 The dimensions of the churns often exceed the belief of those who have 

 not explored them, and few persons travelling over any of the roads 

 near ^litcheldean, or from Bream to Lj duey and Coleford, in fact, 

 over nearly all sides of the Forest near the crop of the limestone, are 



