. The testimony of the rocks; . species from the same locality, it must havemeasured about thirty inches in length. But fragments ofAmerican leaves have been found more than six inches inbreadth, and whose length cannot have fallen short of fortyinches. The Tseniopteris, as its name bears, is regarded asa fern. From, however, the leathern-like thickness of someof the Sutherland specimens, — from the great massivenessof their midrib, — from the rectilinear simplicity of theirfibres, — and, withal, from, in some instances, their greatsize, — I am much disposed to believe that in our Scotch,mayha
. The testimony of the rocks; . species from the same locality, it must havemeasured about thirty inches in length. But fragments ofAmerican leaves have been found more than six inches inbreadth, and whose length cannot have fallen short of fortyinches. The Tseniopteris, as its name bears, is regarded asa fern. From, however, the leathern-like thickness of someof the Sutherland specimens, — from the great massivenessof their midrib, — from the rectilinear simplicity of theirfibres, — and, withal, from, in some instances, their greatsize, — I am much disposed to believe that in our Scotch,mayhap also in the American species, it may have been thefrond of some simple-leaved Cycas or Zamia. But thepoint is one which it must be left for the future satisfac-torily to settle; though provisionally I may be permittedto regard these leaves as belonging to some Cycadaceous ASS ON THE LESS KNOWN plant, whose fronds, in their venation and form, resembledthe simple fronds of Scolopendrium, just as the leaves of Fig. 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. 143.
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