-550 MR ROBERT KIDSTON ON 



contour, but the leaf-cushions in the line of the axis, on the most raised part of the larger 

 branch, have suffered more from pressure than the leaf-cushions on the lateral portions of 

 the stem, or those on the smaller branch. The smaller branch shows only a few Halonial 

 scars as it is broken-over a short distance above the point at which they begin to 

 appear, — the lower half of the arm showing no such scars.* 



Both on the Halonial branch, and the other parts of the fossil, the characteristic 

 leaf-cushions of Lepidophloios are shown. Those on the Halonial branch hold their 

 normal position to the stem, the leaf-scar being at the lower end of the downward 

 directed cushion. PI. II. fig. 8a, a, b, show two cushions, x 2, drawn in their actual 

 position to the axis of the stem.t Those on the main stem, and on the other fork, 

 from some cause which I cannot fully explain, are so twisted round from their normal 

 position that the two lateral angles of the leaf-cushion lie parallel with the axis of growth, 

 and consequently the leaf-cicatrice also holds an abnormal position, and thus appears to 

 occupy one of the lateral angles of the leaf-cushion. (PL II, fig. 8a, c; 8b, d, e.) 



These points are illustrated in the figure, | natural size, given on PL II. fig. 8. A is 

 the stronger and larger branch, which has suffered more from pressure than B, on which 

 the Halonial scars occur. On the arm B the leaf-cushions are directed downwards, as in 

 typical Lepidophloios laricinus. Figs. 8a, a, b, show some of the leaf-cushions as they 

 occur on the stem, and the arrows on fig. 8 show their position on the fossil. On the 

 stem A, fig. 8, at c, the leaf-cushions are swung round, and the leaf-cicatrices point 

 outwards. I think this has been brought about by pressure acting in the direction of the 

 axis, which has twisted the leaf-cushions outwards on each side. It must also be 

 observed, in connection with this, that the cushions lying on the central and more 

 elevated part of the stem form a flattened band along its axis. This curious alteration 

 in the natural direction of the cushions has caused their longer axes to lie parallel with 

 the axis of growth, and thus in their general outline they simulate the leaf-cushions of 

 Lepidodendron. The leaf-cushions are also swung from their natural position on part of 

 the lower portion of the branch B, and are directed outward in a similar manner to that 

 already described, as at fig. 8, B, c. From the characters possessed by this fossil, there 

 cannot remain any doubt as to its being a Lepidophloios bearing a Halonial branch. 



I have already referred to the specimen of Lepidophloios Scoticus, Kidston (Lejn- 

 dophloios laricinus, Macfarlane [not Sternberg), given by Dr Macfarlane in the 

 Trans. Bot. Soc. Edin., vol. xiv. pi. vii., and I have a similar specimen in my 

 possession, from the Midlothian Oil Shales, which shows the union of Halonia and 

 Lepidophloios. Of this specimen I give a figure, reduced to about \ natural size, on 

 PL II. fig. 6. At fig. 6a are shown the leaf-cushions, x 2. 



At PI. II. fig. 5 is given, natural size, a portion of a Halonial branch of another 



* It might be argued from this specimen that, as only one row is seen, the branch had not more than two 

 rows of Halonial scars in all, but it must be remembered that they commence irregularly and are spirally 

 arranged. 



t All the other figures of leaf-cushions, x 2, figs. 8a, c ; 8b, d, e, are also drawn in their present position in regard 

 to the axis of the specimen. 



