President's Address. 389 



Mr Tait in 1898 found a species of Mesacanthus and some 

 badly-preserved Ostracods, which Professor T. Rupert Jones 

 considered to resemble Devonian forms. This is the first 

 record of Ostracods from the Lower Old Red Sandstone of 

 Scotland. By means of these discoveries the Lome strata 

 are shown to be of the same age as those of Forfarshire to 

 the south of the Grampians, and not, as might seem more 

 natural, to those of the Morayshire basin, a long tongue of 

 which stretches far westwards across Inverness-shire along 

 the line of the Great Glen. 



With regard to the correlation of the Lower Old Red 

 Sandstone strata on both sides of the Carboniferous rocks in 

 the central valley, Dr Traquair had identified the head-shield 

 of a Cephalaspis of C. Lyelli type from the Lower Old Red 

 Sandstone of Lesmahagow in Lanarkshire, which was dis- 

 covered by Mr William Clarkson, and presented to the late 

 Dr Hunter-Selkirk. A similar form of Cephalaspis has 

 also been found in equivalent strata near Lanfine, in Ayr- 

 shire, within the same region. These records show that the 

 two great groups of conglomerates, sandstones and volcanic 

 rocks, although separated by overlying newer Palaeozoic rocks, 

 are of the same age, and are probably connected beneath. 



Dr Traquair has also demonstrated the close relationship 

 of the Fish Fauna of the Lower Old Red Sandstone of 

 Scotland, on the south side of the Grampians, with that of 

 the west of England and the Welsh border. 



In his study of the Fishes of the Old Red Sandstone, Dr 

 Traquair shows that not a single species and only two genera 

 are common to the Lower Old Red Sandstone beds south of 

 the Grampians and those of the Moray Firth basin north of 

 that range, or, in other words, in strata belonging to Lakes 

 " Caledonia " and " Orcadie " respectively. On the hypothesis 

 that these deposits may have taken place simultaneously in 

 separate land-locked basins, such a divergence might be 

 accounted for; but Mr Kidston informs me that not one 

 species of Plant is common to the two sets of strata, so that 

 a strong presumption is raised that they were laid down at 

 two different geological periods. Other lines of evidence 

 also tend towards this latter conclusion. 



