Fossil Plants, 137 



(" horse-tails"), and other similar plants. Another common OALLEET 

 genus of the same age is Calamites, which is usually found in ^ 

 the form of ribbed casts of the hollow pith of the stem ; cones 15*18*^**** 

 and leafy branches of Calamites are by no means rare, and Table- 

 are known as Calamostachys, Aster ophyllites, Calamocladux, etc. ^'^ 

 Among the ferns may be mentioned the genera Neuropleris, 

 Alethopteris, Sphenopteris, Pecopteris, and others, of which good 

 examples are exhibited in the table- and wall-cases. In Table- 

 case 28 a few specimens may be noticed under the name Spiropteris^ 

 showing the circinate vernation characteristic of fern fronds. Oa 

 the under-side of the fossil fronds remains of sori and sporangia 

 are occasionally met with, and by a microscopical examination 

 of these it has been found that many of the Coal- measure ferns 

 are nearly related to a few surviving tropical genera included in 

 the family MarattiacecB. Some good specimens of Sphenopteris and 

 other genera from the Carboniferous Limestone of Rhyl are shown 

 in Table-case 27. Another interesting genus of Coal- measure 

 plants is Sphenophyllum, with its whorls of wedge-shaped leaves, 

 attached to a comparatively slender stem. Thanks to the mineral- 

 ization of the tissues of fragments of the stems, leaves, roots, and 

 fructification, we possess a fairly complete knowledge of its his- 

 tological structure; its exact botanical position is, however, not 

 absolutely settled, and it occupies a somewhat isolated position 

 among Palaeozoic Cryptogams. 



The curious fossils from Dudley known as Palaoxyns, shown 

 in Table-case 31, have long been a puzzle to palaeontologists; 

 but are now regarded by many as the egg- cases of fishes. 



In Table-case 26 and Wall case 15, a few Permian plants are 

 exhibited; among these the silicified stems of tree-ferns from 

 Saxony and other districts are of special interest. The charac- 

 teristic Permian fern Callipteris is represented by a few specimens, 

 also the large species of CaJamites. 



In Wall-cases 15 and 16 there are some examples of the fern-hke 

 plant Glossopteris, a genus widely distributed in Upper Palseozoic 

 and Lower Mesozoic rocks of the southern hemisphere, and winch 

 gives its name to the Glossopteris flora of India, Australia, Africa, 

 and South America. 



Of Teiassic plants there are but few examples. In Wall-case 1 5 

 will be found some large specimens of sandstone casts of hquiseittes 

 from the German Trias; this plant seems to have had the form 



