. The testimony of the rocks; . some of its congeners resembled the fronds of the pinnateferns. I have already referred to the close resemblance whichcertain Cycadaceous genera bear to certain of the fernfamily. In at least two sj^ecies of Pterophyllum, — JP,comi^tum and P, oninus^—the divisions of the leaflets^eem little else than accidental rents in a simple fiond; inP. Nelsoni they are apparently nothing more; and similardivisions, evidently, however, the effect of accident, andless rounded at their extremities than in at least P. comp-ttwiy we find exhibited by some of the Helmsdale speci-
. The testimony of the rocks; . some of its congeners resembled the fronds of the pinnateferns. I have already referred to the close resemblance whichcertain Cycadaceous genera bear to certain of the fernfamily. In at least two sj^ecies of Pterophyllum, — JP,comi^tum and P, oninus^—the divisions of the leaflets^eem little else than accidental rents in a simple fiond; inP. Nelsoni they are apparently nothing more; and similardivisions, evidently, however, the effect of accident, andless rounded at their extremities than in at least P. comp-ttwiy we find exhibited by some of the Helmsdale speci- FOSSIL FLORAS OF SCOTLAND. 489 mens of Tseniopteris (See Fig. 142, p. 488.) But what-ever the nature of these simple fronds, they seem to impart Fig. PECOPTERIS OBTUSIFOLIA. much of its peculiar character, all the world over, to theflora of the Oolitic ages. The compound ferns of the formation are numerous,and at least proportionally a considerable part of themseem identical in species with those of the Oolite of Eng-land. (See Fig. 143.) Among these there occur Pecopte-ris Whitbiensis, JPecopteris obtusifolia, Pecopteris insig-nis,—all well marked English species; with several has, besides, its apparent ferns, that seem to be new — 490 ON THE LESS KNOWN (Fig. 144)—tliat are at least not figured in any of the fossilfloras to which I have access, — (Fig. 145), — such as a welldefined Pachypteris, with leaflets broader and rounder than Fig. 144.
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