Va. XXIV.] FOSSIL TEEES OF COAL. 481 



part of the Swansea valley, four stems of upright Sigillarice were seen 

 in 1838, piercing through the coal-measures of S. Wales ; one of them 

 was 2 feet in diameter, and one 1 3-J feet high, and they were all found 

 to terminate downwards in a bed of coal. " They appear," says Sir 

 H. De la Beche, " to have constituted a portion of a subterranean 

 forest at the epoch when the lower carboniferous strata were formed." * 



In a colliery near Newcastle, say the authors of the Fossil Flora, a 

 great number of Sigillarice were placed in the rock as if they had re- 

 tained the position in which they grew. Not less than thirty, some 

 of them 4 or 5 feet in diameter, were visible within an area of 50 yards 

 square, the interior being sandstone, and the bark having been con- 

 verted into coal. The roots of one individual were found imbedded 

 in shale ; and the trunk, after maintaining a perpendicular course and 

 circular form for the height of about ten feet, was then bent over so as 

 to become horizontal. Here it was distended laterally, and flattened 

 so as to be only one inch thick, the fiutings being comparatively dis- 

 tinct.f Such vertical stems are familiar to our miners, under the name 

 of coal-pipes. One of them, 72 feet in length, was discovered, in 1829, 

 near Gosforth, about five miles from Newcastle, in coal-grit, the strata 

 of which it penetrated. The exterior of the trunk was marked at in- 

 tervals with knots, indicating the points at which branches had shot off. 

 The wood of the interior had been converted into carbonate of lime ; 

 and its structure was beautifully shown by cutting transverse slices, so 

 thin as to be transparent. (See p. 40.) 



* These " coal pipes " are much dreaded by our miners, for almost 

 every year in the Bristol, Newcastle, and other coal-fields, they are the 

 cause of fatal accidents. Each cylindrical cast of a tree, formed of 

 solid sandstone, and increasing gradually in size towards the base, and 

 being without branches, has its whole weight thrown downwards, and 

 receives no support from the coating of friable coal which has replaced 

 the bark. As soon, therefore, as the cohesion of this external layer is. 

 overcome, the heavy column falls suddenly in a perpendicular or 

 oblique direction from the roof of the gallery whence coal has been 

 extracted, wounding or killing the workman who stands below. It is 

 strange to reflect how many thousands of these trees fell originally in 

 their native forests in obedience to the law of gravity ; and how the 

 few which continued to stand erect, obeying, after myriads of ages, the 

 same force, are cast down to immolate their human victims. 



It has been remarked, that it; instead of working in the dark, the 

 miner was accustomed to remove the upper covering of rock from each 

 seam of coal, and to expose to the day the soils on which ancient 

 forests grew, the evidence of their former growth would be obvious. 

 Thus in South Staffordshire a seam of coal was laid bare in the year 

 1844, in what is called an open work at Parkfield Colliery, near 



* Geol. Report on Cornwall, Devon, and Somerset, p. 143, 

 f Linclley and Hutton, Foss. Flo., Part. 6, p. 150. 

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