Study of the fauna from a newly discovered fossiliferous outcrop of the Cove Lower Marine Band in Thornton Burn, East Lothian, has led to the correlation of this horizon with the Redesdale Ironstone in Northumberland and has thereby demonstrated the first palaeontological link between the Upper Calciferous Sandstone in S.E. Scotland and the Lower Limestone Group in N.E. England. The collection of D1 fauna made from the Thornton Burn outcrop includes goniatites, brachiopods, lamellibranchs, and crinoids. The discovery of Beyrichoceratoides redesdalensis (Hind) gives the first definite indication of the presence of B zone in the Scottish Carboniferous. Faunal lists and descriptions of some of the more interesting species are included in this paper as well as descriptions of the crinoids collected which are given in the succeeding paper by James Wright.

The crinoids collected by Mr. Hugh Wilson from the shales and ironstones of the Calciferous Sandstone Series in the Thornton Burn section in East Lothian are of special interest and are described herein. The list of species is as follows:—

Talanterocrinus redesdalensis sp. nov.

Blothrocrinus thorntonensis sp. nov.

Anemetocrinus wilsoni sp. nov.

Phanocrinus ardrossensis (Wright).

Ureocrinus bockschii (Geinitz).

Ureocrinus doliolus (Wright).

An intrusion-breccia filling a pipe is made of two parts, one of facetted quartzite fragments in a granophyric matrix, the other of calc-silicate-rock fragments in an appinitic matrix. The quartzite fragments are derived from a horizon at least 1,000 ft. below the breccia level, the calc-silicate-rock fragments are local. The mechanism of emplacement of the breccia is considered to be similar to that proposed by H. Cloos for the Swabian tuff-pipes. Neither the granophyre nor the appinite of the Kilkenny pipe is regarded as of magmatic origin.

The use of the term mugearite as a synonym for oligoclase-basalt is discussed. It is shown that the two rock-types, though often agreeing closely in chemical composition, may differ appreciably in their fabric and mineralogy.

There are two alternative hypotheses regarding the relationship of the goniatite-bearing reef limestones to the coral-bearing “massif” limestones. One claims an unconformity between the reefs and bedded limestones, the other a lateral passage from a “massif facies” to “marginal facies”. Surface exposures are such that it is difficult to be convinced of either hypothesis. Details of underground exposures in natural cave systems and associated mine-workings show a clear transition between facies and no trace of unconformity.

An attempt is made to correlate the concept of the fossil lineage with our knowledge of polytypic species. The influence of changing environmental conditions in the geological succession and the relationship between geographical and chronological sub-species is analysed on a theoretical basis. The fossil lineage is considered to be the resultant of combined evolutionary and environmental change. Phenotypic modifications in response to environmental conditions are discussed in relation to the study of variation in fossil communities.

The discovery of a glacial erratic boulder of Shap Granite in South Northumberland is recorded. Erratics of this rock have not previously been reported north of the Penrith area. It is suggested that the boulder was carried into Northumberland by ice flowing eastwards over the Tyne Gap.

Specimens of Diversograptus are described which show conclusively how the two stipes arise from the sicula. This is also the first record of the genus occurring in Britain

Certain amygdaloidal rocks in Skye have formerly been interpreted as lavas in which the matrix of the amygdales has been replaced by, or alternatively metamorphosed into, material such as one expects in intrusions. It is now claimed that the amygdales formed in intrusions in normal fashion

The suggestion that the Skye amygdaloidal gabbro represents amygdaloidal basaltic lava in which the grain-size has been coarsened by recrystallization does not imply “an unusual type of metamorphism” as Bailey supposes. Whereas recent lava-flows are fine-grained, older flows, particularly pre-historic examples, commonly have a doleritic or gabbroic grain-Size. Bore-hole investigations in Yellowstone Park indicate that such increase in grain-size is a consequence of the long-continued through-passage of gases and water escaping to the surface. Bailey's own observation that amygdales within the Skye amygdaloidal gabbro “interrupt the form of the bigger feldspars” provides evidence that the bigger feldspars are younger than the amygdales, and that the rocks containing them have therefore recrystallized