493 
PARTIAL DENUDATION OF COAL DURING THE CARBONIFEROUS 
EPOCH. 
We have received from Mr. Buddle an interesting paper upon a 
curious phenomenon in the Forest of Dean, improperly called the 
Horse. Fault, being neither a slip nor dislocation, but only an in- 
terruption of the continuity of a bed of coal, called the Coleford 
High Delf, produced by the thinning out of the coal and substitu- 
tion of sandstone in its place. The extent of this Horse has been 
traced about two miles in length, with a breadth varying from 
170 to 340 yards. Besides the total absence of coal in this inter- 
rupted portion of the High Delf seam, the upper surface of this 
seam on each side of the so-called Horse presents an undulating 
line, causing the thickness of the coal to vary considerably, whilst 
its lower surface is symmetrical with the subjacent floor of shale, 
which continues uninterrupted, across the space occupied by the 
Horse. The_bed of sandstone next above this High Delf coal- 
seam is very thick (in one place 94 yards), and occasionally inter- 
spersed with pebbles of quartz and fragments of coal, and angular 
fragments of indurated sandstone containing casts of coal-plants. 
That portion of it which is called the Horse, fills the space sup- 
posed to have once been occupied by the denuded portion of the 
coal-bed. Mr. Buddle considers this denudation, and also the undu- 
lations on. the upper surface of the coal, to have been caused by 
currents of water passing over and removing portions of the stratum 
of vegetable matter which formed the coal before the deposition of 
the sandstone, which has filled these inequalities on the surface of 
the Coleford High Delf seam, and also the broad interruption of its 
continuity called the Herse Fault. 
It is clear that violent currents must occasionally have been in 
action whilst the carboniferous strata were in progress of accumula- 
tion, for without them no kind of pebbles could have found access 
to the conglomerate beds that occur in this formation ; whilst the 
passage of water over the lower strata of the carboniferous series 
may have torn off fragments both from the lower sandstones and 
the lower seams of coal, which the pebbles derived from them show 
to have been then consolidated. 
BLACK BAND OF IRONSTONE IN SCOTLAND. 
A most important discovery has recently been made in the coal 
formation of the West of Scotland, of several beds of ironstone (lo- 
cally called the Black Band), which are of such great importance in 
the manufacture of iron, that its application to the smelting furnace 
has lately raised the value of a single estate at Airdrie more than 
10,0007. per annum. ‘There are several beds of this ironstone, va- 
rying from fourteen to twenty-two inches in thickness; they contain 
very little clay, and nearly as much carbonaceous matter as serves 
to calcine the iron ; for this reason it is more valuable than the clay 
ivonstones hitherto used, of which in this Scotch coal-field there are 
sixty-six. As it is probable that similar beds of this most valuable 
