(7.) Lepidodendron (from Dr. Rankin's collection). About 1¼ inch in diameter. Secondary spirals 10 D, 15 S, 25 D, 40 S. Divergence = 5/(13×5) (Quinquejugate arrangement).
(8.) Lepidodendron (Dowanhill, Glasgow, Possil Sandstone series). Trunk about 1 foot long, and 1 foot in diameter. The upper portion exhibits secondary spirals 35 D, 56 S, 91 D; thus indicating a 7-jugate arrangement, with divergence = 8/(21×7). The arrangement on the middle and lower portion is indistinct and confused; so much so as to render any determination of the arrangement doubtful.
B. Series, ⅓, ¼, 2/7, 3/11, etc.
(9.) Lepidodendron (Messrs Merry and Cunningham's Clayband Iron-Pit, Carluke). Stem 2 inches in diameter. Secondary spirals 18 S, 29 D, 47 S. Divergence = 21/76.
C. Series, ¼, 1/5, 2/9, 3/14, etc.
(10.) Lepidodendron (R. B. Garden, Edinburgh, Museum). Stem somewhat flattened, 1-1½ inch in diameter. Secondary spirals 9 D, 14 S, 23 D, 37 S. Divergence = 13/60.
(11.) Lepidodendron (Redhaugh, near Edinburgh, Mr. Peach). Stem somewhat flattened, ¾ to ½ inch in diameter. Secondary spirals 9 S, 14 D, 23 S, 37 D. Divergence = 13/60.
D. Series, 1/5, 1/6, 2/11, 3/17, 5/28, etc.
(12.) Knorria taxina (Stockbriggs, Lesmahagow,—Hunterian Museum). About 1 inch in diameter. The specimen consists of a main stem and one of the branches into which it has forked. On the main stem the secondary spirals are 6 D, 11 S, 17 D. Divergence = 5/28 (series, 1/5, 1/6, 2/11, 3/17, 5/28, etc.)—On the branch the secondary spirals are 8 S, 13 D. Divergence = 8/21 (ordinary series, ½, ⅓, 2/5, ⅜, etc.)