1849.] 



BROWN ON ERECT SIGILLARI^. 



357 



The exact position of the tree with reference to the underlying coal 

 is shown in the section fig. 6. Immediately over the coal there is a 



Fig. 6. 



Coal seam. 



bed of hard shale six inches in depth, in which no fossils are found ; 

 this is overlaid by a softer shale abounding in coal plants ; all the up- 

 right stumps which I have examined are rooted in the six-inch shale ; 

 the crown of the base of that which I am now describing is just four 

 inches above the coal ; its roots dip gradually downwards until they 

 come in contact with the coal at about eighteen inches from the centre 

 of the tree, and then spread out over its surface. When this fossil 

 was brought out of the mine, the under side was covered up with hard 

 shale, to which about one inch of coal adhered ; in cutting away this 

 layer of coal I met vdth the termination of a perpendicular root im- 

 mediately in contact with the coal, which I carefully developed ; pro- 

 ceeding in this manner, my patience was amply rewarded by the dis- 

 covery of a complete set of conical tap roots arranged in the order 

 represented in fig. 7, which is an horizontal section of the inverted 

 base or underside of the 

 stump, on a scale of one- 

 twelfth of the natural 

 size. It will be observed 

 that the horizontal roots 

 branch off in a remark- 

 ably regular manner, the 

 base being first divided 

 into four equal quarters 

 by deep channels running 

 from near the centre to- 

 wards the points indi- 

 cated by the letters i, k, 

 I, m; an inch or two fur- 

 ther on each of these 

 quarters is divided into 

 two roots, which, as they 

 recede from the centre. 



