Intelligence and Miscellaneous Articles. 533 



diphyodont dentition ; some of these genera being strictly carni- 

 vorous, some herbivorous, and others omnivorous. 



[Professor Owen's paper was illustrated by the unique specimen 

 of the Pliolophus, carefully divested of its matrix ; and by highly 

 finished drawings of its dental structure.] 



2. " On some Remains of Terrestrial Plants in the Old Red Sand- 

 stone of Caithness." By J. W. Salter, Esq., F.G.S. 



An extensive series of plant-remains from the Devonian series of 

 the North of Scotland have been made by Messrs. J. Miller and 

 R. Dick of Thurso, by Mr. Peach of Wick, and by Dr. Hamilton 

 in Orkney ; and, a comprehensive series having been submitted to 

 the Director-General of the Geological Survey, Mr. Salter offered 

 the present communication to incite Botanists to a more critical 

 examination of this old flora. The fossils occur in a dark-grey flag- 

 stone, which is often marked with impressions of Annelide-burrows 

 in pairs. Most of the specimens consist of glossy black coaly 

 matter, either in large compressed stem-like fragments, sometimes 

 3 feet long and 4 inches broad ; or in equally long, but narrower, 

 curved, and occasionally branched forms, which the author regards 

 with some doubt as roots. The stem-like specimens are delicately 

 fluted, but not traversed by joints ; and their microscopic structure 

 is similar to that of coniferous wood, especially of the Arau- 

 caria. The bituminous substance of these plant- remains is obliquely 

 and closely cleaved, the fissures being often filled up with siliceous 

 matter. In form these fossils resemble some specimens {Apui-oxylon) 

 from the Upper Devonian rocks of Thuringia, discovered by Richter, 

 and lately figured and described by Unger. 



There are also some smaller, tapering, and branched specimens, 

 which appear to be branchlets of the same trees that have afforded 

 the stems and roots above noticed ; and some still smaller branched 

 specimens, bearing occasional tubercles on the branchlets, are re- 

 garded by the author as the smaller roots of these trees, and repre- 

 senting the tubercular rootlets of many of the existing Coniferae. 



A new species of Lycopodites (L. Milleri) was also described ; 

 and some specimens of Lepidodendron were referred with liesitation 

 to Unger's L. nothum (Transact. Vienna Acad. 1856). 



The strata from which these plants were obtained form part of the 

 Middle Old Red group of Sedgwick and Murchison, and of the 

 Lower Old Red of Hugh Miller. Dlpterus, Diploptertis, and Astero- 

 lepis are the prevailing genera of fish that accompany the plants. 



LXX. Intelligence and Miscellaneous Articles. 



ON THE VELOCITY OF SOUND IN SOLIDS, LIQUIDS, AND ELASTIC 

 FLUIDS, AND ON THE CORRELATION OF THE PHYSICAL PRO- 

 PERTIES OF BODIES. FIRST PART. BY A. MASSON. 



GEOMETRICIANS have summed up the principal jihysical pro- 

 perties of bodies in a single formula, which expresses the velo- 

 city of sound. Although the laws wliicli they have found have not 

 always been confirmed by experiment, they may be regarded as a 



