38 



SCIENCE-GOSSIP. 



[Feb. ], 18G6. 



Brongniart, on botanical grounds, to be the roots of 

 Sigillaria, and recent discoveries have confirmed 

 this opinion. Sir Charles Lyell, in company with 

 Dr. Dawson, examined several erect Sigillaria in 

 the sea cliffs of the South Joggins, in Nova Scotia, 



Fig. 48. Neiiropteris'gigantea. 



and found that, from the lower extremities of the 

 trunk, they sent out Stigmaria as roots, which 

 divided into four parts, and these again threw out 

 eight continuations, aud these again divided into 

 pairs. 



f 



Fig. 49. Odontopteris Brardii. 



Two other gigantic trees filled the forests of t this 

 period : these were Lepidodendron carneatum and 

 Lomatop/iloyos crassicaule, both belonging to the 

 family of Lycopodiaceee ; which includes, in our age, 

 only very small species. The trunk of the Lomuto- 

 phloyos threw out numerous branches, which termi- 

 nated in thick tufts of linear and fleshy leaves. 



The Lepidodendrons, of which there are about 

 forty species known, have a cylindrical stem or trunk, 

 bifurcated in the branches— that is, the branches 

 were evolved in pairs. The extremities of the 

 branches were terminated by a fructification in the 

 form of a cone formed of linear scales, to which 

 the name of Lepidostrobus has been given. In many 

 of the coal-fields fossil cones have been found, to 

 which this name has been given by earlier paleon- 

 tologists. They sometimes form a nucleus of 

 concrete balls of clay ironstone, and are well pre- 

 served, having a conical axis, surrounded by scales 

 compactly imbricated. The opinion of Brongniart 

 is now generally adopted, that they are the fruit of 

 the Lepidodendron. At Colebrookdale and else- 

 where these have been found as terminal tips of a 

 branch of a well-characterised Lepidodendron. Both 

 Hooker and Brongniart place them with the Lycopods, 

 having cones with similar spores and sporangia like 

 that family. Nevertheless, many of these branches 

 seem to have been sterile, simply terminating in 

 fronds or elongated leaves. Most of them were 

 large trees. One tree of S. Sternbergii, nearly fifty 

 feet long, was found in the Jarrow Colliery, near 

 Newcastle, lying in the shale parallel to the 

 plane of stratification. Fragments of others found 

 in ,the same shale indicated, by the size of the 

 rhomboidal scars which covered them, a still greater 

 size. 



Fig. 50. Lonchopterii Bricii. 



The ferns composed a great part of the vegetation 

 of the carboniferous period, both in the herbaceous 

 and arborescent form. Eerns differ chiefly in some of 

 the details of the leaf. Pecopteris, for instance 

 (fig. 47), has the leaves once, twice, or thrice pin- 

 nated with the leaflets adhering either by their whole 

 base or by the centre only ; the midrib running 

 through to the point. Neuropteris (fig. 48) has 

 leaves divided like Pecopteris, but the midrib does 

 not reach the apex of the leaflets, but divides 

 right and left into veins. Odontopteris (fig. 49) 

 has pinnatifid leaves like the last, but its leaflets 

 adhere by their whole base to the stalk. Lonchop- 



