This paper is the first of a series of reports on the detailed investigations of the Gelogy of Central Vestspitsbergen arising out of the Cambridge Spitsbergen Expedition, 1949. While subsequent publications will consist almost entirely of new data, the purpose of this paper is primarily to compile information obtained previously. Following the Introduction, there is a review of the published literature as it affects the area as a whole; this has been attempted at length to save repetition in the later chapters and in any subsequent papers. The later chapters include a detailed study of the Carboniferous to Lower Permian of Billefjorden, using unpublished material which has been made available from several expeditions of the Scottish Spitsbergen Syndicate, some results from the Cambridge Spitsbergen Expedition, 1938, and from that of 1949 in so far as they affect this particular study. It therefore represents an original contribution resulting from a compilation and checking in the field of the work of a number of geologists.

The palæontological results are being worked out separately, but within the area, exposures are sufficient to provide a reliable correlation of the Carboniferous to Lower Permian succession recorded in a number of vertical sections. We have found that the very variable facies can best be grouped into the following formations, retaining so far as possible the earlier names:

The major Devonian diastrophism was followed by erosion, deposition, and again erosion in the Devonian. Culm of estuarine facies was then deposited in a basin due to subsequent movements along a great north-south Devonian fault-belt. They rest on the Devonian to the west of the fault-belt and on pre-Devonian to the east. After the Culm, local conglomerates reflect movements along this fault-belt at the western margin, and in the centre of the basin evaporites are developed. Although a number of disconformities can be traced, there is no important unconformity in the basin. The widespread transgressions recorded outside this area, equivalent to the base of the Cyathophyllum Limestones and again to that of the Brachiopod Cherts, are marked within the area by distinct change of facies but no angular relationship of the bedding.

The distribution of these various formations is shown in a geological map to a scale of 1:100,000, which is the first comprehensive topographical and geological map of the whole area to be published.

The early development of the mammary glands and of hair follicles in the mouse and the rabbit has been investigated by means of mitotic counts, by histochemical methods and by cultivation in vitro. In the first stage of the formation of both types of rudiment a thickening of the epidermis appears as a consequence of an aggregation of cells, not of a local elevation of the mitotic rate. During this stage alkaline phosphatase is absent from the cells and the content of ribose-nucleic acid reduced. Both these substances appear in higher concentrations later, and their relation to processes of growth and differentiation is discussed. Essentially similar phenomena are found in rudiments cultivated in vitro, which, however, frequently suffer a degeneration by a process of keratinisation.

The paper presents the results of an investigation of the distribution and biology of flies of the family Drosophilidæ in Scotland. Methods of sampling the population are described and notes are given on the breeding of many species in the laboratory. All earlier records of Drosophilidæ in Scotland are brought together for the first time, and the new species, Drosophila silvestris, is described.

The stratigraphical succession of the Jurassic rocks of Eathie (Cromarty) is described and a list of the fossils collected by the writer from the Kimmeridgian beds given. The fauna, which is of mixed Boreal and Mediterranean affinity, shows that the strata belong to the three basal Eo-Kimmeridgian ammonite zones proposed by Spath. The occurrence of an abundant microfauna is recorded and the palæontology of the varied molluscan forms is discussed. Three new lamellibranch species are described. A short account of the Upper Oxfordian beds which outcrop at Bow Buoy Skerry, 1 mile south of Eathie, is given.

Sixteen new species of trilobites are described and named, and thirty species are figured. The specimens were collected from a small exposure of mudstones at Craighead Quarry; most of the species are only known from this one exposure. The occurrence of several species which show strong affinities with forms from higher horizons indicates that the mudstones are more recent than other Balclatchie Group (Lower Caradocian) deposits.

The Creag Strollamus area lies about three miles to the north-west of Broadford, and presents in miniature all the formational and structural elements of the plutonic region of Skye.

The pre-plutonic substructure of the area consists of Torridonian, largely sandstones and grits, overthrust at low angles upon Cambrian limestones. The thrust plane has been thrown into a number of gentle folds on N.E.-S. W. axes, and has suffered displacement by faults of small throw having the same N.E.-S.W. trend. Owing to later erosion the Torridonian sediments remain as a very thin veneer over much of the area, but thicken rapidly towards the north-west.

Tertiary volcanics, very largely basalt lavas, were extruded upon a surface of considerable relief, but have now been partly removed to reveal large stretches of Torridonian. Subsequent movements included the development of a number of N.W.-S.E. or N.N.W.-S.S.E. faults, usually of small throw, as well as a general warping of the area, so that the volcanics are now inclined north-eastwards at angles around 30 degrees.

Particular attention is directed to the disposition of the sub-volcanic surface in relation to the thrust plane. In a south-easterly direction the erosion surface gradually converges on the thrust plane and ultimately, in the area of the Broadford gabbro, descends beneath it.

Gabbros form a number of masses of widely varying size, but evidently represent sheeted bodies, formerly of greater continuity. Gabbro occurs only in localities where, as considerations of structure show, the former presence of volcanics may reasonably be inferred, the sub-volcanic surface representing the downward limit of gabbro just as it limits the volcanics themselves. Within the gabbro masses internal structures can be recognised which agree with those in the basalts.

Petrographically the close relationship between gabbros and basalts is confirmed by the occurrence of grading contacts and the presence within the gabbros of relic textures and small-scale structures, including amygdales, comparable with those of the basalts. It is therefore concluded that the gabbros developed by the transformation of the pre-existing volcanic rocks.

Just as the downward limit of gabbro in the structure of the area is the sub-volcanic surface, so the granites are confined upwards by this surface and downwards by the thrust plane. Granite occurs in place of Torridonian in the pre-plutonic structure. The variation in habit of the granites from “boss-like” to sheeted in a south-easterly direction is to be correlated with this observation.

Having regard to the preservation of pre-granite structures, often of considerable complexity, it does not appear possible that the granites have been emplaced by the mechanical displacement of Torridonian. Transformation of Torridonian, essentially in situ, is therefore considered the more probable explanation. Support for this view is provided by the nature of the junctions between Torridonian and granite. These are invariably merging and show, at least on a limited scale, that granitisation has indeed occurred.

Kentuckia, from the basal Carboniferous, is the earliest bony fish in which neurocranium and dermal skeleton are well known. The dermal bones show that it belongs to the central family Palæoniscidæ of Berg. They have no obvious generalised characters, however, and are chiefly distinguished by a deeply embayed hind margin to the skull roof, no dermohyals and an elongated postorbital bone. These features suggest a greater affinity with the few known Devonian types than with those of the Carboniferous.

The neurocranium has a considerable likeness to Watson's Kansas Palæoniscids A and B, and confirm Watson's view that this is the fundamental type of actinopterygian cranium. Kentuckia is slightly more generalised than the others in having a paired myodome and a less excavated dorsal surface. The notochord in all three has a long anterior extension like that shown in Pteronisculus (Glaucolepis) of the Eo-Trias by Nielsen. This latter fish is similar to the earlier ones if allowance is made for a greater proportion of cartilage. In the discussion reference is also made to the following: the degree of ossification of these fishes, the nature of the cranial fissure and its homologues, the distribution of the third, fourth, fifth and seventh nerves, and the origin of the cranial wall in the orbitotemporal region.

Certain additions are made to Watson's account of Palæoniscids A and B, particularly concerning the interior of the braincase. A new form, C, is also described.

The vertical and horizontal distributions of important plants and animals on exposed rocky shores in Caithness are described, and comparisons are made with other shores of the British Isles. The environmental conditions which cause a marked uplift in the zonation of inter-tidal species in Caithness are considered.

Evidence is given that many of the Mesozoic, geosynclinal serpentines of Turkey are deep-sea lavas, and that they functioned as efficient fertilizers of surface waters leading to rich crops of radiolaria now preserved in cherts and limestones. Furthermore, in anticlinals at Ankara and Alaca Höyük, Palæozoic, Triassic and Jurassic rocks in the condition of a tectonic mélange are overlain unconformably by Upper Cretaceous and Eocene; while, in associated synclinals at Ayas and Kirsehir, crystalline schists and granites, probably Palæozoic or earlier, emerge from beneath unconformable Oligocene. It is suggested that these crystallines are parts of a Pontic nappe which advanced southwards during Upper Cretaceous times, in part overriding and breaking local rocks to yield the Ankara Mélange, in part bulldozing them forwards to form the Taurus Mountains. The displacement along the Anatolian Thrust at the base of the invading Pontic nappe is reckoned at about 350 km.

The Mollusca possess two growth axes associated with the body and the mantle/shell respectively. Evolution of the Lamellibranchia involved assumption by the mantle/shell of responsibility for growth and form; also the formation of anterior and posterior adductors. Change from this dimyarian to a heteromyarian and finally monomyarian condition involved changes in the relations of body and mantle/shell. These are considered with regard to their two major axes in the saggital plane. Although body form may be greatly influenced by changes in that of the mantle/shell, its proportions are only altered where the body is attached by byssus. Then the anterior half may be reduced and the anterior adductor finally lost. This occurs in many Anisomyaria, these monomyarians being divisible into five groups according to habit. Apart from the Limidæ, all are bilaterally asymmetrical. In those which have lost the foot, both axes of the body are effectively lost. Primary pallial attachment is lost but secondary attachment has been achieved in most cases. In the Tridacnidæ (Eulamellibranchia) the mantle/shell has rotated in the saggital plane in relation to the fixed body with resultant loss of the anterior adductor. There is hypertrophy and extension antero-dorsally of the originally posterior siphonal tissues in which zooxanthellæ are contained. Evolution may have proceeded by way of now extinct heteromyarians such as Lithocardium. In the freshwater Acostœa (Mulleria) the anterior adductor is lost during growth following cementation by one or other valve. The form of the body is little affected. Variation and natural selection account for the variety of form and habit exhibited by these diverse monomyarians.

Since the classical work of Sir Thomas Holland at the beginning of this century on the charnockite series in Peninsular India there have appeared numerous papers describing rocks from all over the world which have been claimed to belong to this series. The rocks from the type area around Madras have now been re-examined, with particular reference to their chemistry and chemical mineralogy, to provide further evidence for their mode of origin.

Following petrographic descriptions, fifteen new analyses of these rocks are presented together with trace element determinations, and these are shown to produce smooth curves on a variation diagram. For several rocks all the constituent minerals have been analysed, and it has thus been possible to discuss the mineralogical location of the various major and trace elements in these rocks. Trace element determinations are presented for the 43 minerals analysed together with those for a further 35 minerals not chemically analysed, and their variation within the mineral species is discussed.

The possible modes of origin of these rocks are considered, and from the evidence obtained they are held to represent a plutonic igneous rock series which has undergone recrystallization in the solid state on being subjected to plutonic metamorphism.

An interpretation of the Tertiary rocks of the area, which are shown to be denudation relics of a gigantic volcano, is found by following the actualistic principle, that is by interpreting the unknown with reference to the known or actual. “Actualistic”, i.e. with reference to actual causes—commonly used by continental geologists—is chosen in preference to “uniformitarian” since the latter stands in contradistinction to “catastrophic”, and is not, therefore, altogether appropriate to some of the more violent aspects of volcanic activity. Gabbros and granophyres, hitherto thought to be plutonic intrusions emplaced within Caledonian granodiorite, are shown to be highly metamorphosed basaltic and rhyolitic lava-flows, agglomerates and tuffs, together with some gabbro sills. These rocks form a layered series which is almost horizontal at Slieve Gullion, and dips at various angles at Foughill and Carrickcarnan. A Tertiary ring-dyke of granophyre and felsite encircles the layered rocks and outlines a caldera within which the basaltic lavas (including pillow-lavas) of Slieve Gullion accumulated. During the formation of a later caldera these lavas became inset within the underlying Caledonian granodiorite. The acid layers of Slieve Gullion represent rhyolites, incandescent tuff-flows, and agglomerates, the materials of which were derived from the Caledonian granodiorite. The time of eruption of these acid rocks is correlatable with periods of caldera formation.

The layered series is dissected by arcuate faults, and contacts previously thought to be intrusive are now demonstrated to be faulted. Transgressive granophyres follow the faults and form intrusion-breccias and net-vein systems with the layered series. Evidence is presented for concluding that these granophyres originated as glassy acid tuffisite—an intrusive pyroclastic rock (Cloos, 1941)—derived from the basement Caledonian granodiorite, and emplaced by rising gas-streams. That the gas sometimes had a temperature high enough to fuse basalt is witnessed by the fact that the basaltic rocks commonly become exceedingly fine grained where they adjoin transgressive granophyre. Such fine-grained edges are cross-cutting to the layers and cannot therefore be interpreted as normal chilled edges. Hybrid rocks, e.g. marscoite, are associated with the transgressive granophyres. They are shown to represent mechanical mixtures of acid tuffisite, carried upwards by rising gas-streams, with fragmented (tuffisitised) and partially fused basic material derived from the walls of the channels. The transgressive granophyres and associated hybrids are related in origin to incandescent tuff-flows, and are regarded as marking the routes by which such flows reached the surface.

The metamorphism of the basaltic flows, and the transformation of the acid layers and transgressive acid tuffisites to granophyre, were probably accomplished during the pneumatolytic and hydrothermal phase of volcanic activity. Transformation of the acid rocks to granophyre involved introduction of K and Si, and removal of Na, Al, Fe, Ca, Ti, P and Mn. Similar chemical interchanges transformed basaltic rocks at Foughill and Carrickcarnan to quartz-dolerites. The subtracted materials have been located in small-scale basic fronts margining granophyres; within masses of gabbro that sank within gas-tuff streams from higher levels; and in dispersed form within the basic rocks of Slieve Gullion.

From the abounding moraines, drainage features (fig. 21) and other marginal indications an attempt has been made to reconstruct the successive phases of the ice in its retreat into the corries of the Highlands and Islands (Pl. I). Two late-glacial stages are recognised. During the first, the Highland Glaciation, an ice-margin ran from the Orkney Islands across the mouth of the Moray Firth to the Buchan and out to sea north of Aberdeen. Twelve substages (A–L) of retreat, arbitrarily selected, have been traced through the country, except in the Moraineless West where they are unrepresented.

At the maximum of the second stage, the Moraine Glaciation, the ice readvanced to the line stage M (beaded line in Pl. I). The retreat from this line, the inner boundary of the Moraineless West and of the 100-foot raised beach (Pl. I), is divided into nine substages (N–V), based upon a consideration of snowlines. Substage N corresponds to the 50-foot raised beach, substage P to an important readvance.

The snowline throughout the late-glacial period ran in the west parallel with the meridians and rose eastwards. The disposition of the snowlines for stage M is given in fig. 22, p. 900.

The distribution of the ice in the British Isles during the North British, Highland and Moraine Glaciations is represented in fig. 23, p. 923.

A Critical survey is given of the spirit-preserved material of Marsupialia in the Royal Scottish Museum, with special reference to the fœtal stages.

Of the crab-eating opossum, 12 mm., 16 mm., 20 mm., 30 mm. and 70 mm. stage pouch-embryos are discussed in detail, and compared with stages already known for D. marswpialis virginianus. A similar series of Dasyurus quoll, varying from 12·2 mm. to 34 mm., is considered, followed by notes on adults of some of the less well-known Dasyuridæ. Three pouch stages are studied in Peramelidæ and comparison made with data in the literature. In the Phalangeridæ fœtal stages of Pseudocheirus lanuginosus, Schoinobates volans, Trichosurus vulpecula and Acrobates pygmœus are included. Macropodidœ are represented by Macropus robustus stages ranging from 16 mm. (3·4 weeks old) to 138·7 mm.

The construction of dams across fresh-water rivers supplying Hydro-Electric schemes has raised the problem of providing less costly methods than mechanical screens for preventing migratory fish from entering inlet and outlet tunnels of water turbines. The paper deals with the possibilities of employing electric screens for such purposes, and gives the results of laboratory investigations followed by site experiments under actual working conditions. Items covered in the fundamental research include (a) a study of trout reactions when subjected to various shapes and strengths of electric fields, and the effects of exposure to them, (b) particulars of electrode arrangements and other factors governing the characteristics of electric fields in waters containing different amounts of impurities, (c) the relative efficiencies in stopping and diverting fish swimming with and against water flows, (d) the conditions necessary for attracting fish to positive electrodes, and (e) some observations on incidental experiments with combinations of lights and electric screens, and with mechanical vibrations. Details are included of the actual screens in operation and the efficiencies obtained from them.

In the latter part of the paper a description is given of an original type of automatic electric fish-counter installed in two Hydro-Electric Station fish-passes in the North of Scotland, for integrating the numbers of ascending salmon and descending kelts through a common orifice.

In Part I brief descriptions are given of the goniatite faunas found at horizons in the Scottish Carboniferous succession; and mainly on the evidence of these faunas, the stages of B, P1; P2, E1; and E2 and A are approximately demarcated. No goniatites suggesting the presence of H, R and G have been seen.

In Part II descriptions are given of certain species of the following genera: Beyrichoceratoides, Anthracoceras, Cravenoceras, Cravenoceratoides, Girtyoceras, Eumorphoceras, Goniatites, Sudeticeras, Dimorphoceras, Neodimorphoceras and a new genus, Cluthoceras.

The type material of Orthocera gigantea J. Sowerby 1819 is refigured and redescribed. Specimens referred to this species by J. Phillips, J. Fleming, F. McCoy and F. S. Wallis have similarly been reinvestigated. The counterpart of the type of Actinoceras simmsii C. Stokes 1840 is also illustrated. Numerous other specimens from England, Scotland and Ireland have been studied. The material is found to be referable to the genus Rayonnoceras Croneis and to embrace a number of species. The calcification of the siphuncular structures is found to be variable in this genus.

The mammalian hair-fibre, together with the “inner root-sheath” (i.e. the axial layers of the follicle wall), grows upward by a proximal addition of cells. Changes in the inner root-sheath are responsible for the final shape and surface sculpture of the fibre. At its distal limit the inner root-sheath disintegrates owing to the effect of a de-keratinizing chemical agent.

A bent, undulated, or “crimped” fibre is due to a differentiated progress of the changes leading to keratinization of the “fibre cortex”. The cells which give rise to a “medulla” are different chemically and less compressible than cortical cells.