SCIENTIFIC SUMMARY. 
273 
4. Sub-order Theropoda (Beast foot). Carnivorous. 
Feet digitigrade ; digits with prehensile claws. 
Pubes coossified in front ; post-pubis present. 
Vertebrae more or less cavernous ; limb bones hollow. 
Family Allosauridce. 
Genera Allosaurus, Creosaurus, and Labiosaurus. 
5. Sub-order Hallopod A (Leaping foot). Carnivorous? 
Feet digitigrade, unguiculate ; three digits in hind foot. 
Metatarsals much elongated ; calcaneum much produced backward. 
Two vertebrae in sacrum ; limb bones hollow. 
Family Hallopodidce. 
Genus Hallopus. 
6 ? Sub-order Cceltjria (Hollow tail). Carnivorous ? 
Family Coduridce. 
Genus Ccelurus. 
Two of the above genera ( Diracodon and Hallopus) are described as 
new in the paper from which this classification is taken. — Silliman's American 
Journal, May, 1881. 
Silurian Plant Remains. — Traces of these fossils were first observed in 
1875 by Hr. Hicks in some shale, interstratified with rather massive beds 
of grit, in Pen-y-glog slate quarry, about two miles east of Corwen. Further 
research has resulted in the discovery of more satisfactory specimens, and in 
showing that they occur at still lower horizons. The fragments are ex- 
ceedingly abundant, in some places being so closely matted together as to 
form a carbonaceous seam over an inch in thickness. Some of the specimens 
are from half an inch to an inch in diameter, and of various lengths, but 
always in a broken condition, indicating that they did not grow in the 
position in which they are now found, but must have drifted here on being 
washed down by river floods. Thin seams of a very pure anthracite, 
showing occasionally indications of plant structure, occur also in the slates 
underlying these beds; and anthracite is frequently found composing the 
nucleus in some large nodules which are found at several horizons in the 
slates. Among the specimens found are some spherical bodies, resembling 
the Pachytheca of Sir J. H. Hooker, from the lower bed of the Ludlow 
series, supposed to be Lycopodiaceous spore-cases ; also numerous minute 
bodies stated by Mr. Carruthers to be united in threes, and to agree with the 
forms of the microspores of Lycopodiacese, both recent and fossil ; and some 
fragments, which may belong tp these plants, and others, probably belong- 
ing to plants described by Dr. Dawson from the Devonian of Canada under 
the name of Psilophyton. The above testify to the existence of a very rich 
land-flora at the time. Mixed up with these, however, are numerous car- 
bonaceous fragments of a plant described also by Dr. Dawson from the 
Devonian of Canada, which he referred to the Coniferse, but which is, 
according to Mr. Carruthers, an anomalous form of Alga. The former 
called it Prototaxites ; the latter renamed it Nematopliycus. Numerous 
microscopical sections, showing the beautiful structure of this interesting 
plant from the specimens found at Pen-y-glog, have been examined by Mr. 
Etheridge and Mr. Newton, and their conclusions agree in the main with 
those of Mr. Carruthers. Mr. Etheridge, however, recognizes here a new 
NEW SERIES, VOL. V. NO. XIX. T 
