120 DR. REDFERN, ON THE TORBANEHILL 



I excepted about the upper two inches of the bed, because 

 the yellow spaces there are much less visible, and there is 

 more uniformity in the appearances of various parts of sections. 

 Yet thougli the yellow matter of the upper part is not so ob- 

 viously marked out into spaces by the dark-brown substance, 

 that part being, I presume, less carbonised than those lower 

 in the seam, the mass consists of alternate patches of yellow 

 and reddisli-brown matter, and presents a very marked differ- 

 ence on horizontal and vertical sections. The vertical sections 

 of this part always show reddish-brown bands or patches, 

 sometimes branching, and always extending in the direction 

 of the laminae of bedding, like the dark-brown bands of ver- 

 tical sections in the lower part of the seam (Plate VII., fig. 2). 

 A very gradual change of appearance is noticed on passing 

 from the upper to the lower parts of the seam, and in each of 

 these parts there are occasional patches which present the 

 ordinary appearances of the other, so I have no doubt that 

 originally both were formed nearly in the same way. 



Crystals which polarise light very highly exist in all the 

 higher parts of the bed, but they are not found in the lower. 

 One is shown in Plate VII., fig. 2. 



4th. Every horizontal section presents a number of more 

 or less rounded or angular bodies, in colour yellow, red, or 

 brown, and in size measuring from 1 -500th to I-2000th of an 

 inch (Plate VIII., fig. 5). Most of them occur singly, but oc- 

 casionally two, three, or more lie close together ; and I have a 

 preparation in which is a group of fifty or sixty of the smallest 

 of these bodies. When they occur singly, I think four or five 

 may generally be seen in a field of the microscope of about 

 l-60th of an inch in diameter. Sections taken from the upper 

 part of the bed are most favourable for their examination, 

 because such sections are of a lighter colour than others, and 

 can be made much thinner than they without breaking. 



In vertical sections, such bodies are always found elongated 

 (Plate VIII., fig. 6), their length being equal to the diameter 

 of the spots shown on horizontal sections, and their breadth 

 varying from l-4000th to l-1300th of an inch. Some of them 

 present the appearances of coiled fibres, and I believe that 

 such are either fragments of scalariform vessels, or portions 

 of fibre, probably from spiral vessels or cells. Others are 

 circular, both on horizontal and vertical sections, and are 

 undoubtedly spherical cells. Many which are somewhat 

 angular have an obviously double outline, like cells with thick 

 walls, and they have small conical or blunt projections stud- 

 ding them externally. Some have lost their definite outline 

 at particular spots, as if they had sufFei'ed from pressure or 



