The occurrence of Monograptus in the Carmichael Burn section of the Midland Valley of Scotland has now been confirmed. A new fauna is described from beds previously regarded as Ludlovian which are here suggested to be of Valentian age. A detailed stratigraphical succession has been established and the structure of the area revised in the light of this new information, most of which was derived from a number of exploratory pits sunk for the purpose. Tentative correlations with the other Midland Valley inliers are attempted and many problems requiring future solution are raised.

Four new species of petrified seeds are described:

1. 1. Eccroustosperma langtonense gen. et sp. nov.—a curved platyspermic seed with two apical lobes of the integument and a rough sclerotesta when mature.

2. 2. Hydrasperma tenuis gen. et sp. nov.—a small slender seed with 8–10 free apical lobes and longitudinal external ridges.

3. 3. Stamnostoma bifrons sp. nov.—a barrel-shaped seed with a nucellar apex and micropyle intermediate in form between Stamnostoma huttonense and Sphcerostoma ovale.

4. 4. Dolichosperma sexangulatum gen. et sp. nov.—a relatively long narrow radiospermic seed with a dense sixangled integument open above and without tentacles or micropyle. The salpinx was probably funnel-shaped.

All four species are assigned to the Lagenostomales.

The Lower Carboniferous fossil Calymmatotheca kidstoni Calder is shown to be a simple seed and is redescribed under the new name Genomosperma kidstoni. A second species G. latens is also described. Genomosperma gen. nov. is of interest in possessing a free nucellus with a lagenostome and short salpinx. The nucellus is surrounded by an integument of about eight lobes which are free from one another and from the nucellus from near the base of the seed. The vascular details of t h e seeds have been studied and in each species pollen has been observed in the pollen chamber.

Genomosperma is compared with various Pteridosperm seeds.

The principal basic components of the Tertiary Carlingford complex are believed to have formed through the differentiation of magma of a high-alumina basaltic type. These rocks, which were once thought to be in the form of a ring-dyke, are shown to occur as a floored and multi-layered intrusion. Four major layers have been recognized. Within each, differentiation through crystal fractions settling under the influence of gravity is believed to have been the chief factor producing chemical variation. The effect of this process is seen in the compositional and modal variations of the gabbroic rocks and their constituent minerals. The variations from bottom to top of each layer correspond to a decreasing temperature of crystallization with height. At the bottoms are gabbros enriched in olivine. At the tops, the gabbros are rich in plagioclase. Throughout the layers, the plagioclases are transitional between the high and low (temperature) structural states. The resemblance of these rocks to other layered intrusions (e.g. Rhum, Bushveld, etc.) is taken as proof of the magmatic origin of the Carlingford layered basic rocks.

The base of the lowest layer is in contact with Silurian sediments and Tertiary basalts. The sediments have been intensely metasomatized with reciprocal contamination of the gabbro immediately above. Greater extremes of metasomatism and mobilization are seen in the sedimentary xenoliths which occur within the gabbros. At the base of the topmost layer of gabbro, a horizontal screen of highly metasomatized Silurian sediments separates that gabbro from the one below.

Torridonian and Lewisian rocks lying in inverted order between the Kishorn thrust and the Moine thrust, and Moine rocks, lying above the Moine thrust, exhibit a remarkable parallelism of structure.

New evidence shows that three sets of minor structures have been developed in the formations during the Caledonian movements. At least two of these sets pre-date the Moine thrust movements. The mylonites, which are not restricted to the vicinity of the Moine thrust outcrop, belong to an earlier movement phase than these structures and are not directly related to the clean-cut thrust movements. They appear to represent narrow zones of shearing and sliding, mainly within the Lewisian gneisses that developed early in the Caledonian orogeny.

There is reason to suppose that the inversion of the rocks to the west of the Moine thrust occurred before the formation of the minor structures recognized in the paper.

The minor structures are described and their order of formation established. The plastic, para-crystalline style of the earlier deformation is contrasted with the post-crystalline brittle style of the later deformations.

A detailed description is given of the fossil pollen floras of two lignite seams associated with the Tertiary igneous rocks of Western Scotland. One of the seams occurs at the base of the lava succession at Ardslignish, Ardnamurchan; the other is exposed at two localities, Shiaba and Bremanoir, within the lava succession on the island of Mull.

Seventy-one species belonging to forty-four genera are described. All the species and two of the genera are new. Comparisons are made with modern pollen grains and some close resemblances are noted between the fossil species and species now living in various distant parts of the world, in particular Eastern Asia, Australasia and North America.

Two new species of fossil seeds are described from the Cementstone Group of Berwickshire. Deltasperma fouldenense is asymmetrically platyspermic, and has large superficial cells chiefly on the more convex side. It is orthotropous but shows no pedicel. Camptosperma berniciense is campylotropous and has a dense integument. A vascular bundle to the chalaza ends at the nucellus base.

Both seeds possess a similar lagenostome and short salpinx; two integumental bundles which expand in the free lobes; a female prothallus with a wide “tent-pole” and about two archegonia; a nucellus adnate to the integument below the lagenostome; and spherical pollen grains in the pollen chamber. The seeds show most affinity with the Lagenostomales.

The Lower Carboniferous seed Samaropsis scotica Calder has been re-investigated from new material and assigned to a new genus Lyrasperma. It is shown to have a nucellar apex with a pollen chamber and a funnel-like structure interpreted as an expanded salpinx. The free parts of the two integumental lobes diverge as apical horns; there is therefore no micropyle. Eurystoma angulare gen. et sp. nov. possesses a similar nucellar apex but is usually quadrangular in section and has four apical lobes. The new genera are placed in the group Lagenostomales although the expanded salpinx is a character new to that group.

The mouthparts and associated structures and the feeding mechanism of two small atyid prawns, Caridina africana and C. nilotica, are described in detail. Both species collect fine particles of food with the chelipeds, which for this purpose are armed with greatly modified spines and setæ, and transfer them rapidly to the mouthparts. Here the food is removed from the chelipeds by a grid-like arrangement of setse on the first maxillipeds and combed from these by the highly modified and teasel-like distal portions of the maxillæ which operate in conjunction with the first maxillipeds as a single functional unit. From these it is passed to the maxillules and thence to the mandibles.

An attempt is made to reconstruct on a functional basis the route by which primitive malacostracans could reach the condition now found in Caridina, and the evolution of chelipeds is discussed.

A Description is given of the distribution and zonation of the dominant intertidal plants and animals found in a survey of rocky shores in Argyll, from Clachan Sound southwards to the south end of the Kintyre peninsula, thence northwards along the east side of Kintyre to Loch Fyne. Particular attention is given to two sheltered lochs, Loch Sween and West Loch Tarbert. Features of special interest in the area include: (i) a very small spring tide range (only 2–4 ft.) on much of the west coast of Kintyre, which results in a very compressed littoral zone by British standards; (ii) an unusual abundance of Chthamalus stellatus, often accompanied by a scarcity of Balanus balanoides, at very sheltered sites in Loch Sween and West Loch Tarbert (this problem is considered separately in Part II of the present paper); (iii) rich lower-shore populations in parts of the lochs, and especially associated with the Linne Mhuirich rapids in Loch Sween. In a concluding discussion the lower shore populations found in the survey area are compared with those observed in the rest of the British Isles. It is concluded that the rich lower-shore populations (often associated with rapid systems) that occur in many of the lochs on the west coast of Scotland constitute a major component of the littoral fauna and flora of the British Isles that has been largely unknown and neglected in the past because of the remoteness of many of the sites.

Glaucophane-Schists and eclogite are associated with ultrabasic rocks, basic intrusions and Ordovician spilitic lavas at Knockormal in the Girvan-Ballantrae complex, South Ayrshire. Detailed mineralogical and chemical data are presented which indicate that the various glaucophane and blue-amphibole rocks have been derived from spilitic lavas. In addition to glaucophane a blue-amphibole related to crossite is also described. While there is no evidence for an introduction of soda, the deformation attending the glaucophanitic metamorphism was accompanied by chemical changes which appear to have occurred at high water-vapour pressures. There is no evidence of any relationship between the eclogite and adjacent glaucophane-rocks. The eclogite, which is highly aluminous, is interbanded with wehrlite, pyroxenite and serpentinite, and represents a particular phase in the crystallization of these ultrabasic rocks.

Well-preserved compression material of Zosterophyllum myretonianum Penhallow from the Lower Old Eed Sandstone in Angus has yielded additional information about the structure of this plant, one of the earliest known types of vascular land plants. It is the earliest plant in which the structure of the epidermal cuticle, stomata and complete tracheids has been clearly demonstrated. The basal regions of the plant are found to consist of branching axes some with arrested or dormant side branches. Simple dichotomy into two equal and similarly orientated branches is rare. H-type branching and some modifications of it are of frequent occurrence in the basal region of the plant. Parts of this region of the plant have no stomata although a cuticle was present. The upright fertile axes rarely branched.

This is a study of the functional morphology of the muscular and reproductive systems of the adult beetle, Atomaria ruficornis (Marsham) made by means of serial sections and dissections. An account is given of the skeleto-muscular system of the head, thorax and abdomen with reference to previous work in this sphere. Wherever possible, the muscles described have been homologized with those of other Coleoptera. In a small number of cases, it has been found necessary to use new names for muscles. The probable mode of action of the mouth-parts and foregut during feeding is described. An account is given of the reproductive organs and genitalia of both male and female beetles; the muscular system of the genitalia in both sexes is described fully, and the functioning of the genitalia is discussed.

Stamnostoma huttonense is a petrified seed assigned to the Lagenostomales. The open upper part of its integument shows no lobes or chambers. The short wide salpinx is inserted within a relatively wide “micropyle” and is partly invaginated into the top of the lagenostome which usually contains pollen. The female gametophyte is known, it has a domed “tent-pole” and three archegonia.

The paired cupules had sixteen or more terminal segments. Abscission scars indicate that four seeds were borne in each cupule though some were abortive. The cupules if preserved as compressions would resemble the genus Calathiops Göpp.

Tristichia ovensi is a Lower Carboniferous Pteridosperm known from both petrifactions and compressions. The stems possess a triradiate protostele and some show secondary xylem. The petioles have a butterfly-shaped trace and dichotomize repeatedly forming very slender axes sometimes bearing minute terminal pinnules similar to those of Moresnetia zalesshyi Stockmans. Associated with Tristichia are seeds and cupules of Stamnostoma huttonense and less frequently compressions of seeds borne terminally on very fine dichotomous pedicels.

Chemical analysis of samples of the Older Granodiorite, Co. Donegal, Ireland, shows that it has a geographical variation in which Si, K and O increase, Na is about constant and all other major elements decrease in amount from east to west. There is a high degree of positive linear correlation between Mg and Fe2 + Fe3 which implies derivation of these elements from some previously existing ferromagnesiam mineral in which the appropriate ratio was maintained. There is a low degree of negative linear correlation between Na and K which implies that these elements are mobile and independent of each other.

The chemical relationships of the granodiorite to its pelitic country rocks are shown and discussed. The relations are such that the preferred hypothesis for the origin of the granodiorite is one of influx of Na, K and Ca ions in an alumino-silicate medium. Country rocks are diluted by this influx and it is unnecessary to assume any great migration of Mg and Fe. With time the nature of the influx changes—Ca decreases in amount whereas Na, K and Si all increase but K and Si to a very much greater extent than Na.

The members of the Rosses Granitic Ring Complex have been chemically analyzed. The data are presented as averages with 95 per cent confidence limits for individual elements. A limited amount of crystallization differentiation is demonstrated when the major units—the biotite microgranite sheets, the porphyry dykes, the ring granites and the grey and pink microgranite sheets—are compared with one another. This involves an increase in Si, K, a decrease in Ti, Al, Fe, Mg, Ca and P, but Na (and Mn) remain constant. The ring granites G1-G4 undergo very little differentiation and variations in their composition, except for Si, are ascribed mainly to heterogeneity.

The origin of the magma which gave rise to the complex is due to the palingenesis of the Older Granodiorite under the influence of a Na, K, alumino-silicate influx. This magma was the source of the biotite microgranite sheets and, after differentiation, the granites G1 and G2, together with some of the grey and pink microgranite sheets. After a period of quiescence a second influx produced the similar magma which was the source of the porphyry dykes and, after differentiation, gave rise to the granites G3 and G4, the Newer Granite bosses and the late grey and pink microgranite sheets.

The distribution and zonation of Chthamalus stellatus and Balanus balanoides on British coasts is reviewed, and it is shown that the very sheltered waters of Loch Sween and West Loch Tarbert are unusual in that Chthamalus occurs there in greater quantity than in any other sheltered (British) locality, and the upper limit of Chthamalus is consistently higher, relative to other species, than elsewhere in shelter. The lower limit of Chthamalus is generally at a rather high level on these shores even when bare rock occurs below. Balanus balanoides, on the other hand, is often scarce or absent at the same sheltered sites. The physical conditions in the lochs (water temperatures, tides, winds, sunshine, rainfall) and their seasonal variations are examined and it is shown that there probably is a unique succession of environmental factors that would favour Chthamalus and operate against Balanus at critical times of the year. It is suggested that Chthamalus occurs higher than Pelvetia in the lochs because of a greater tolerance of irregular and often prolonged periods of desiccation. The failure of Chthamalus to occupy the middle and lower shore when Balanus is absent indicates that competition between the two barnacles does not alone determine their vertical distribution on the shore. A tentative hypothesis is developed showing how the very local distribution of Chthamalus and the level occupied on the shore might be related to responses of the cyprids to light and to a supposed requirement of emersion during the early stages on the shore.