the Bolton Railway^ at Dixon Fold^ near Manchester. 155 



which geologists are not agreed. They ai'e six in number, 

 and stand nearly erect on a seam of coal nine inches thick, which 

 lies near the centre of the Lancashire coalfield, declining 

 about 17° from the perpendicular, which corresponds with the 

 dip of the strata from the horizontal plane, so that they are 

 still perpendicular to the plane of the bed. They arc in a 

 stratum of argillaceous shale which rests upon the coal, and 

 gradually passes upwards into an ordinary coal-measure sand- 

 stone ; and of a similar sandstone the trees themselves chiefly 

 consist. 



No. 1 is 8 feet inches high, and at the base has a diameter 

 of 5 feet, and a little higher of 3 feet. No roots can be seen, 

 but the swollen base shews that large ones must originally 

 have existed. At two feet above the base there is a remarkable 

 horizontal band of blue shale containing many thin plates of 

 sandstone ; it is about nine or ten inches thick, and, as will be 

 seen in the sequel, is a very important feature. The surface of 

 this and all the trees, had, when first discovered, a thin shelly coat 

 of coal, which has, for the most part, since fallen off ; and the 

 trunks have the furrowed appearance of decorticated Sigillaria?, 

 with more or less regular ribs and furrows. At the base only 

 a few cicatrices or scars could be perceived. 



No. 2 is but the base of a large tree with similar ribs and 

 furrows, with a lateral sinus, the sides of which are strongly 

 marked wath wavy raised lines, very like the surface of a 

 gnarled oak after the removal of the bark. But the most im- 

 portant features of this specimen are its enormous roots, which 

 strike off from the trunk in different directions, standing 

 downwards into the coal ; but they are abruptly cut off when 

 they reach its surface. The principal roots have a diameter 

 of 20 inches to 2 feet, and their surface is marked with ribs 

 and fm-rows of a peculiar character. 



No. 3, 4, and 6, are smaller, and need no particular notice, 

 except that the latter is marked with the long prominent scars 

 of a decorticated Lepidodendron. 



No. 5 is a fine specimen, 5 feet 3 inches high, diameter of 

 the base 3 feet 6 inches, and at the top 2 feet 4 inches. The 

 main root before it bifurcates has the extraordinary diameter 

 of 4 feet 6 inches, but this may have been increased by pres- 



