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.

Active or recently-active, large-scale quarrying operations within the Carboniferous Limestone Series of this area, and ranging in location from the near-junction areas to points about half a mile removed from the southern boundary of the main littoral Trias outcrops, have afforded excellent sections displaying remnants of a former Triassic cover. It is considered unlikely that the latter outliers, of limited dimensions, occur in areas further removed than about one-third of a mile south of the existing limits of the main Triassic outcrops.

The conditions under which ptygmatic veins develop occur when the country-rock—as in a granitized area—is locally less competent or more yielding than quartzo-felspathic magma which may intrude it. Veins therefore which are being driven forward by pressure from behind, will buckle plastically if they encounter a resistance during injection, and a succession of such buckles will produce a typical ptygmatic vein. The amplitudes of the flexures so formed depend on the relative physical states of the vein and host-rock; so for any particular vein there is usually a more or less constant size for the tortuosities developed. The mechanism explains several features observed in examples of ptygmatic veins, and has been reproduced experimentally in the laboratory. The contortions are therefore not necessarily due to the deformation of the veins by post-injection flowage or tectonic movements of the country-rock.

Numerous small lakes in the Naini Tal region of Kumaon have long attracted attention but no satisfactory explanation of their origins has been presented. The various lakes did not all originate in the same way in spite of their proximity, but there must be common underlying conditions to explain the abundance of lakes in this small area. These conditions appear to be the very recent and very local irregular uplift of a mass of diverse lithological units riding over an irregular sub-thrust surface.

The orientation of the optical indicatrix in synthetic and volcanic plagioclases differs from that in plutonic and metamorphic plagioclases, the former “optics” being commonly known as “high-temperature”, and the latter as “low-temperature”. The difference between the two series is most marked at the sodic end and decreases towards An70. The conclusion that the difference, though small, still persists in the range An70 to An100 is shown to be unwarranted on the evidence available. Grave doubt is thrown on the supposition that temperature is the controlling factor in determining the type of optics by Tuttle and Bowen's failure to synthesize low-temperature albite, even at low temperatures. It is known, however, that some low-temperature plagioclases (e.g. in albite-schists) have grown without the intervention of melt. The real antithesis may therefore be between plagioclases crystallized from melts, and those developed during the metamorphic reconstitution of rocks.

From the fact that the plagioclase, quartz, and alkali feldspar of undoubted magmatic rocks such as quartz-porphyry and rhyolite are respectively systematically different from those of granite it is concluded that the latter is a metamorphic rock

A zone of intense metamorphism extends for six feet on both sides of a nearly vertical fifteen feet wide olivine dolerite dyke. Adamellites have been converted in situ to rocks resembling quartz porphyries, and mobilization of cordierite gneiss has been effected. Petrography and chemical analyses show that metamorphism is not purely thermal. Although little actual fixation of doleritic “end liquors” took place in the wall rocks the cause of these remarkable contact effects is ascribed to hydrothermal activity near the “blind end” of the dyke.

In previous reconstructions of Gondwanaland the Falkland Islands have been placed in a position intermediate between the Cape Province and Northern Argentina. In the present paper it is suggested on structural, tectonic, and stratigraphical grounds that it would be preferable to position the Falkland Islands due east of the Eastern Province coast, thus completing the truncated Karroo Basin, the missing part of which has until now been suspected to be concealed beneath the ice-capped Queen Maud Land, Antarctica.

The section described is a well section, 20 miles from the nearest Millstone Grit outcrop. Attention is drawn to the rhythmic sedimentation resulting from the intermittent subsidence that was occurring at the time.

The writer describes the relief forms and destructional processes occurring in a group of granite hills in Damaraland, South-West Africa. The hills are attributed to the dissection of a former erosion surface by rejuvenated streams. Drainage incision has followed longitudinal and diagonal joint lines, which control the orientation and sub-division of individual groups of granite domes. The destruction of granite masses by plating, or the unloading of Unweathered shells, produces the dome outline, whereas the development of vertical jointing leads to granite tors. Domes may be cleaved along transverse joints to form secondary domelets, or split longitudinally to form narrow whalebacks. The former are lowered by plating to flat dome forms the latter are reduced by marginal fracturing, here termed mural weathering. Further wastage is by slow granular disintegration on low granite outcrops.

The ontogeny of Dalmanitina olini Temple (Upper Ordovician) is described on the basis of specimens from Scania and North Wales. The development is similar to that of D. socialis (Barrande), but good preservation has enabled some detailed changes in the cephalon to be followed. The protaspid and early post-protaspid stages bear an anterior pit in each axial furrow opposite the frontal lobe. The protaspid anterior glabellar furrow becomes joined to this pit by an oblique furrow, and forms with the latter a composite oblique furrow which develops into the adult anterior-glabellar furrow. This mode of development is considered probably to be common to all Phacopids: the significance of the anterior pits in this family is discussed. Preliminary observations are made on the growth-rates of various parts of the glabella, and the frontal lobe is found to grow in length (sag.) at a rate approximately equal to that of the rest of the glabella.

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).

Practically monomineralic masses of talc, of magnesite, and of chlorite are formed in talc-magnesite-chlorite-rocks as a result of localized shearing and associated hydrothermal activity within deformation-belts.

The history of this block of low-grade metamorphic sediments begins with sedimentation, followed by strong deformation. Intrusion of spessartite dykes then took place, after which movement was resumed with deformation of the spessartites. Next followed jointing and the production of peculiar structures here called joint-drags. The final episode was one of block faulting, to which the formation of the Muness Phyllite Block itself as a graben is due.

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.

Thermal metamorphism of Silurian sediments at a gabbro contact took place under pyroxene-hornfels facies conditions. The most common hornfels is essentially composed of pyroxene and labradorite; its chemical composition compares with that of average gabbro. The hornfels is believed to have been metasomatically altered, probably basified, during metamorphism.

Valley fill exposed in chalk pits at Barrington consists of two beds, which differ markedly in lithology and in the nature of the molluscan fauna contained in them. The lower bed is thought to predate the Boulder Clay, which caps the high ground, and the upper bed is considered to have been derived from the Boulder Clay. The lower bed, a chalk solifluxion, apparently spread into the Cam valley and covered the famous Hippopotamus bed. Both the Hippopotamus bed and the present depth of the Cam valley, therefore, probably predate the Boulder Clay.

In an attempt to dissect the granitization process in an area of regional metamorphism, it is suggested that granite is forcibly injected during strong compression, that the compressional wave passes upwards and outwards in advance of the magma, and that several changes take place before its arrival. Six stages in this process are recognized in the Cooma and Albury districts of N.S.W.: (1) Regional Metamorphism, (2) Superimposed Thermal Metamorphism, (3) Permeation without Magmatic Addition, (4) Addition from an Attenuated Magma, (5) Formation of a Potassic Wave-Front, and (6) Injection of the Magma as Concordant Intrusions. The conditions favouring granitization are discussed and the question of basic fronts is considered.

Eight spore types from Upper Carboniferous coals of Britain are described and figured, and their stratigraphical distribution and possible relationships are discussed. One new genus and five new species are instituted.

On Orval, in the Isle of Rhum, Tertiary plateau lavas directly overlie the granophyre of the ring-complex. Judd considered that the Orval basalts rest unconformably upon an old land surface cut in the granophyre; but on the supposed existence of veining and metamorphism later workers, in particular Geikie and Harker, concluded that the granophyre had intruded the volcanic pile. The author's re-examination of the Orval rocks supports Judd's early interpretation.