This genus embraces a very large proportion of the ferns which have contributed to the formation of the coal, and whose leaves and stems are preserved in the associated strata. The originals of many species were undoubtedly arborescent, and attained a large size; some leaves four feet wide, and of a proportionate length, have been observed. More than one hundred species are determined. An American species (_Pecopteris Sillimani_) is figured in illustration of certain botanical terms, _Lign. 16_, _ante_, p. 110. Several species of Pecopteris occur in the fluvio-marine oolitic deposits near Scarborough, and leaves in fructification are not uncommon: _fig. 1, Lign. 27_, represents a leaflet slightly magnified. [Illustration: Lign. 28. Lonchopteris Mantelli. _Wealden, Tilgate Forest._ Fig. 1 and 2.--Leaflets magnified, to show the reticulated venation. 3.--A fragment of a frond; _nat._ ] [Sidenote: FOSSIL FERNS. LONCHOPTERIS.] Lonchopteris (_spear-leafed._) _Lign. 28._--Leaves many times pinnated; leaflets more or less adherent to each other at their base, traversed by a midrib; secondary veins reticulated. The three known species which compose this genus resemble the living ferns of the genera Lonchitis, Woodwardia, &c. Two have been found in the coal-measures, and one species in the Wealden formation of England and Germany (_Foss. Tilg. For._ pl. iii.) This last appears to have been a delicate plant; for though fragments are very common in the micaceous grits and clays, any considerable portion of a leaf is of rare occurrence. M. Graves found the same fern near Beauvais in France, in strata, which, from the presence of the fresh-water limestone called Sussex marble, are supposed to be referable to the Wealden epoch. This Lonchopteris is widely spread through the Wealden; and occurs also in the Greensand. Mr. Morris first observed it in the iron-sandstone of Shanklin Chine.[86] [86] Geol. I. of W. 2d _Ed._ p. 230. [Illustration: Lign. 29. Fig. 1.--Phlebopteris[87] Phillipsii. _Oolite, Scorborough._ 2.--Phlebopteris propinqua, _showing fructification_. ] [87] Comptopteris of M. Ad. Brongniart. Phlebopteris (_veined-leaf_). _Lign. 29._--Leaves pinnated; leaflets with the margin entire, or crenulated, the midrib strong; secondary veins anastomosing by arches, with large angular spaces, often unequally disposed; the finer veins are simple or divided; the apex sometimes free. The fructification is punctiform, and placed at the apices of the veins. The foliage of these remarkable ferns has been mistaken for the leaves of dicotyledonous plants; but M. Brongniart has demonstrated that they belong to the present family. Six species have been found in the Oolite and Lias. [Illustration: Lign. 30. Clathropteris meniscoides. _Portion of a leaflet: the original 1-1/2 ft. long._ _Wealden? Scania._] [Sidenote: FOSSIL FERNS. CLATHROPTERIS.]