One of the writers' main aims has been to help to prepare the way for a new approach to problems in which the natural occurrence of forsteritic olivines is a vital factor. Variation in their shapes and textural relations in minor intrusions, lavas and melts is examined and the historical development of concepts of their growth and resorption, particularly in magmas, is traced. Particular attention is focused on the olivines of picritic, minor intrusions. It is concluded that in the interpretation of olivine shapes there has been discrimination in favour of magmatic resorption rather than skeletal crystallization. From a wide and detailed survey of forsteritic olivines it is established that they tend to grow rapidly and that their phenomenal variation in habit and shape is probably due to a specific growth sensitivity to slight environmental differences. Concepts of the physical conditions leading to skeletal crystallization are briefly reviewed and discussed.

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 arid climate of the Altiplano has preserved a volcanic history of ∼11 million years at the Aucanquilcha Volcanic Cluster (AVC), northern Chile, which is built on thick continental crust. The AVC has a systematic temporal, spatial, compositional and mineralogical development shared by other long-lived volcanic complexes, indicating a common pattern in continental magmatism with implications for the development of underlying plutonic complexes, that in turn create batholiths.

The AVC is a ∼700-km2, Tertiary to Recent cluster of at least 19 volcanoes that have erupted andesite and dacite lavas (∼55 to 68 wt.% SiO2) and a small ash-flow tuff, totalling 327 ± 20 km3. Forty 40Ar/39Ar ages for the AVC range from 10·97 ± 0·35 to 0·24 ± 0·05 Ma and define three major 1·5 to 3 million-year pulses of volcanism followed by the present pulse expressed as Volcán Aucanquilcha. The first stage of activity (∼11–8 Ma, Alconcha Group) produced seven volcanoes and the 2-km3 Ujina ignimbrite and is a crudely bimodal suite of pyroxene andesite and dacite. After a possible two million year hiatus, the second stage of volcanism (∼6–4 Ma, Gordo Group) produced at least five volcanoes ranging from pyroxene andesite to dacite. The third stage (∼4–2 Ma, Polan Group) represents a voluminous pulse of activity, with eruption of at least another five volcanoes, broadly distributed in the centre of the AVC, and composed dominantly of biotite amphibole dacite; andesites at this stage occur as magmatic inclusions. The most recent activity (1 Ma to recent) is in the centre of the AVC at Volcán Aucanquilcha, a potentially active composite volcano made of biotite-amphibole dacite with andesite and dacite magmatic inclusions.

These successive eruptive groups describe (1) a spatial pattern of volcanism from peripheral to central, (2) a corresponding change from compositionally diverse andesite-dacite volcanism to compositionally increasingly restricted and increasingly silicic dacite, (3) a change from early anhydrous mafic silicate assemblages (pyroxene dominant) to later biotite amphibole dacite, (4) an abrupt increase in eruption rate; and (5) the onset of pervasive hydrothermal alteration.

The evolutionary succession of the 327-km3 AVC is similar to other long-lived intermediate volcanic complexes of very different volumes, e.g., eastern Nevada (thousands of km3, Gans et al. 1989; Grunder 1995), Yanacocha, Perú (tens of km3, Longo 2005), and the San Juan Volcanic System (tens of thousands of km3, Lipman 2007) and finds an analogue in the 10-m. y. history and incremental growth of the Cretaceous Tuolumne Intrusive Suite (Coleman et al. 2004; Glazner et al. 2004). The present authors interpret the AVC to reflect episodic sampling of the protracted and fitful development of an integrated and silicic middle to upper crustal magma reservoir over a period of at least 11 million years.

More than twenty igneous intrusions, of widely varying composition and mainly in explosion-breccia pipes, cut the Appin Quartzite, Appin Limestone, Appin Phyllites and Cuil Bay Slates of the Dalradian Series which show evidence of a long and complex structural history. Early phases of tectonics and metamorphism (garnet-amphibolite facies) were followed by the dominant deformation of the region, referred to as main phase. The major structure of the Cuil Bay Synform, together with a series of parasitic folds, were developed during this phase together with a strong, retrogressive, regional cleavage. Late phase deformation acting prior to the development of the pipes produced steeply plunging open folds and box folds, of brittle type. The superimposition of these structures on main phase parasitic antiforms, in banded sequences of competent and incompetent units, produced dome-shaped structures with pipe-shaped zones of intensely fractured and brecciated rock. Late phase deformation after igneous intrusion was associated with the Great Glen Fault. The structural elements which exercised the dominant controls on the location and form of the pipes were the main phase regional cleavage, the main phase parasitic antiforms, the late phase steeply plunging open folds and the axial planes of the late phase box folds and open folds.

A generalized sequence of events for a number of the pipes is: (1) explosive activity with shattering and brecciation, (2) emplacement of variable but generally hornblende-rich igneous types, representing crystallization at high to moderate gas pressure, (3) the emplacement of augite diorites or kentallenites representing crystallization at low gas pressure and (4) the emplacement of generally small bodies of leucodiorite–granodiorite, possibly representing secondary hybrid liquids. The other pipes show one or more of these events and the sequence is that expected in volcanic activity associated with the build up and release of pressure on the breaching of structural traps (formed by the Appin Quartzite). Explosive activity took place on the sudden release of gas when the gas-charged basic magma moved into the dome-shaped interference structures with their pipe-shaped zones of much fractured and brecciated rock.

Precise information about the food of the brown trout is somewhat scanty, especially as regards the relation existing between diet and environmental fauna.

(a) Day (1887) points out that “food which (brown) trout consume is of various descriptions. … They do not object to little fish, as the minnow, loach, sticklebacks, etc., water rats, young birds, frogs, snails, slugs, worms, leeches, maggots, flies, beetles, moths, waterspiders and even a lizard.” He concluded that the “tastes of some differ from those of their companions.”

Harris is supposed to derive its name from the Gaelic “na hardibh,” a designation signifying “the heights.” The term is appropriate in that the most mountainous parts of the Long Island lie within its boundaries.

South Harris forms a natural geographical division for it is divided, from North Harris by a narrow neck of iand at Tarbert separating the eastern from the western seas. This isthmus is less than half a mile across. In addition to South Harris proper, this memoir deals also with the Isle of Scalpay and neighbouring islets off the north-east coast, the Isle of Taran-say on the north-west, and several islands off the south-west coast in the Sound of Harris, of which the principal ones are Ensay, Killegray, Groay, Lingay, and Gilsay.

The dust particles floating in our atmosphere are every day demanding more and more attention. As our knowledge of these unseen particles increases, our interest deepens, and I might almost say gives place to anxiety, when we realise the vast importance these dust particles have on life, whether it be those inorganic ones so small as to be beyond the powers of the microscope, or those larger organic ones which float unseen through our atmosphere, and which, though invisible, are yet the messengers of sickness and of death to many—messengers far more real and certain than poet or painter has ever conceived.

The Archæan rocks of the southernmost part of the parish of Harris in the Outer Hebrides have long been known to include not only a wide variety of gneisses of igneous origin, but also a group of paragneisses which, along with presumably contemporaneous formations in Glenelg, Tiree, Iona and elsewhere, probably represent the most ancient sediments in Britain. Apart from early references by Macculloch (1819) and Heddle (1878, 1888, 1901), for practically all our present information on these gneisses we are indebted to Jehu and Craig (1927), who have made a reconnaissance survey over the whole chain of the Outer Hebrides and whose work forms the standard account of the geology of this region.

The present paper gives a description of the gneisses around the village of Rodil, a district of somewhat complex petrography and metamorphic history. The paragneisses present include crystalline limestones, calc-silicate rocks, garnet-kyanite-gneisses, graphite-schists, quartzites, and other schistose and gneissose rocks less easily described by short titles. These sediments have been intruded by sills or sheets of basic to ultrabasic composition, now represented by gneisses of the composition of eclogite, garnet-amphibolite, amphibolite, peridotite, pyroxenite, saxonite, websterite, and a series of rocks referred to under the portmanteau name of metagabbro—types akin to pyroxene-granulites and basic charnockites, often garnet-bearing, but locally with pyroxene and garnet replaced to a varying extent by hornblende and biotite. There is also present a large mass of anorthosite-gneiss bordered by metagabbros, both the feldspathic and basic rocks bearing frequent schlieren of eclogite, garnet-amphibolite, and amphibolite. The complex is traversed locally by acid and basic pegmatite dykes and sheets.

The arid climate of the Altiplano has preserved a volcanic history of ∼11 million years at the Aucanquilcha Volcanic Cluster (AVC), northern Chile, which is built on thick continental crust. The AVC has a systematic temporal, spatial, compositional and mineralogical development shared by other long-lived volcanic complexes, indicating a common pattern in continental magmatism with implications for the development of underlying plutonic complexes, that in turn create batholiths.

The AVC is a ∼700-km2, Tertiary to Recent cluster of at least 19 volcanoes that have erupted andesite and dacite lavas (∼55 to 68 wt.% SiO2) and a small ash-flow tuff, totalling 327 ± 20 km3. Forty 40Ar/39Ar ages for the AVC range from 10.97 ± 0.35 to 0.24 ± 0.05 Ma and define three major 1-5 to 3 million-year pulses of volcanism followed by the present pulse expressed as Volcán Aucanquilcha. The first stage of activity (∼ll-8 Ma, Alconcha Group) produced seven volcanoes and the 2-km3 Ujina ignimbrite and is a crudely bimodal suite of pyroxene andesite and dacite. After a possible two million year hiatus, the second stage of volcanism (∼ 6-4 Ma, Gordo Group) produced at least five volcanoes ranging from pyroxene andesite to dacite. The third stage (∼4-2 Ma, Polan Group) represents a voluminous pulse of activity, with eruption of at least another five volcanoes, broadly distributed in the centre of the AVC, and composed dominantly of biotite amphibole dacite; andesites at this stage occur as magmatic inclusions. The most recent activity ( 1 Ma to recent) is in the centre of the AVC at Volcán Aucanquilcha, a potentially active composite volcano made of biotite-amphibole dacite with andesite and dacite magmatic inclusions.

These successive eruptive groups describe (1) a spatial pattern of volcanism from peripheral to central, (2) a corresponding change from compositionally diverse andesite-dacite volcanism to compositionally increasingly restricted and increasingly silicic dacite, (3) a change from early anhydrous mafic silicate assemblages (pyroxene dominant) to later biotite amphibole dacite, (4) an abrupt increase in eruption rate; and (5) the onset of pervasive hydrothermal alteration.

The evolutionary succession of the 327-km3 AVC is similar to other long-lived intermediate volcanic complexes of very different volumes, e.g., eastern Nevada (thousands of km3, Gans et al. 1989; Grander 1995), Yanacocha, Perú (tens of km3, Longo 2005), and the San Juan Volcanic System (tens of thousands of km3, Lipman 2007) and finds an analogue in the 10-m.y. history and incremental growth of the Cretaceous Tuolumne Intrusive Suite (Coleman et al. 2004; Glazner et al. 2004). The present authors interpret the AVC to reflect episodic sampling of the protracted and fitful development of an integrated and silicic middle to upper crustal magma reservoir over a period of at least 11 million years.

Some time ago my brother, Professor William Thomson, pointed out to me a curious conclusion to which he had been Ied, by reasoning on principles similar to those developed by Carnot, with reference to the motive power of heat. It was, that water at the freezing point may be converted into ice by a process solely mechanical, and yet without the final expenditure of any mechanical work. This at first appeared to me to involve an impossibility, because water expands while freezing; and, therefore, it seemed to follow, that if a quantity of it were merely enclosed in a vessel with a moveable piston, and frozen, the motion of the piston, consequent on the expansion, being resisted by pressure, mechanical work would be given out without any corresponding expenditure; or, in other words, a perpetual source of mechanical work, commonly called a perpetual motion, would be possible. After farther consideration, however, the former conclusion appeared to be incontrovertible; but then, to avoid the absurdity of supposing that mechanical work could be got out of nothing, it occurred to me that it is necessary farther to conclude, that the freezing point becomes lower as the pressure to which the water is subjected is increased.

A new temnospondyl, Thabanchuia oomie gen. et sp. nov., is described from three skulls and associated postcranial elements from the Early Triassic Lystrosaurus Zone of South Africa. T. oomie is the best-preserved member of the Tupilakosauridae, a temnospondyl taxon previously known only from disarticulated material from Russia and Greenland, but shown here to include Kourerpeton bradyi, an articulated specimen with no locality data but presumed to be from North America. Tupilakosaurids are the only Mesozoic survivors of the dvinosaurian radiation, the sister group to the archegosaurs of the Permian plus the stereospondyl clade. It is postulated that their occurrence in Russia, Greenland and North America represents a reinvasion from Gondwana, where they survived the Late Permian extinctions along with the stem of the stereospondyl clade. T. oomie is probably immature but, like other members of the dvinosaurian clade, was fully aquatic, had ossified ceratobranchials and most likely an increased number of vertebrae and reduced limbs. Like Tupilakosaurus, T. oomie had diplospondylous centra.

Felsic I-type granites and associated volcanic rocks of Carboniferous age are extensively developed over an area of 15,000 km2 in northern Queensland. These granites have been subdivided into four supersuites: Almaden, Claret Creek, Ootann and O'Briens Creek.

Granites of the Almaden Supersuite are intermediate to felsic (56-72% SiO2) and are characterised by high K2O, K/K(K + Na), Rb, Rb/Sr, Th, U and relatively low Ba and Sr. The Claret Creek Supersuite granites are a little more felsic (65-77% SiO2), and are chemically distinctive, having higher A12O3, CaO, Na2O and Sr, and lower K2O, Rb, Th and U than granites of the Almaden Supersuite.

Granites of the Ootann and O'Briens Creek supersuites all contain more than 70% SiO2 and these comprise more than 90% of the total area of granites. These two supersuites are characterised by low Sr, Sr/Y and large negative Eu/Eu*, with the more evolved rocks becoming strongly depleted in TiO2, FeO* MgO, CaO, Ba, Sr, Sc, V, Cr, Ni, Eu, CeN/YN and K/Rb, and enriched in Rb, Pb, Th, U and Rb/Sr. Granites belonging to the O'Briens Creek Supersuite contain significantly higher abundances of HFSE, HREE and F (0·2-0·5 wt%) than those of the Ootann Supersuite, and as such have developed some characteristics of A-type granites.

Geochemical and isotopic properties suggest that all granites are of crustal derivation. The granites of all supersuites have very similar initial 87Sr/86Sr and εNd of 0·710 and −7·0–−8·0, respectively, except where they outcrop within Proterozoic country rocks, when they have more evolved εNd (−8·0–−11·0). Depleted-mantle model ages cluster around 1·5 Ga. The isotope systematics and geochemistry indicate that these granites were not derived from the equivalents of any exposed country rocks.

Models for the petrogenesis of these granites all appear to require the involvement of a long-lived and isotopically homogeneous crustal protolith, that most probably underplated the crust in the Proterozoic. Granites of the two more felsic supersuites were either derived by varying degrees of partial melting from this protolith of andesitic to dacitic composition, and/or were produced by a two-stage process by remelting of intermediate rocks similar in composition to the mafic end-members of the Almaden Supersuite. The resulting primary partial melts for the Ootann and O'Briens Creek supersuites underwent extensive, high-level, feldspar-dominated, crystal fractionation.

The adaptive character and possible course of evolution—following permanent byssal attachment—of the heteromyarian form in the Bivalvia is considered in relation to the eulamellibranch Dreissenacea and the filibranch Mytilacea. In both it assumes the extreme condition of ventral (anterior) flattening representing a high degree of adaptation for epifaunal life. The presence of a shell shelf in the umbonal regions of Dreissena and Septifer is associated with the greatest degree of ventral flattening; it permits retention of the anterior adductor and its attachment to parallel surfaces. Enlargement of the posterior regions of the visceropedal mass and the posterior territory of the mantle/shell involves formation of an elongated opisthodetic ligament. That of the Dreissenacea, here initially described, is of unique complication. In primitive infaunal isomyarians an organ of locomotion through soft substrates, in these heteromyarians the foot becomes essentially concerned with byssal attachment with which much the greatest part of the small anterior and large posterior retractors becomes exclusively concerned. Although strikingly similar to the Mytilacea, the Dreissenacea which now inhabit slowly moving or still, silt-laden freshwaters would seem most probably to have evolved under very different marine conditions prior to their relatively recent migration into freshwaters.

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.

The Tetraconodontinae Lydekker, 1876 are a subfamily of pigs (Suidae) with a great variety of dental adaptations, such as greatly enlarged or reduced premolars, enlarged posterior molars, hypsodonty, enlarged incisors etc. The essence of most of these adaptations can be described very well by simple biometry. Size increase of the last molars has proved to be of importance in African biostratigraphy. However, it appears that members of different lineages have been mixed up.

Tendencies in relative premolar size indicate that the 21 species known can be grouped in three tribes: (1) the Tetraconodontini, with very large or even extremely enlarged premolars and, in one of the lineages, a tendency to enlarge the posterior molars; (2) the Nyanzachoerini new tribe, characterised by moderately enlarged or even reduced premolars and with a tendency to increase the length of the posterior molars by the addition of distal cusps; and (3) the Parachleuastochoerini new tribe, with relatively long but narrower premolars. Both Nyanzachoerini and Tetraconodontini include species that were placed previously in Conohyus and Nyanzachoerus.

A very long gradually evolving lineage in the Nyanzachoerini, spanning 13 Ma, is documented. In the last 5 Ma of this lineage, M3 length increased at such a rate that a (sub)species can be recognised about every 0·7 Ma. Slightly lesser rates of evolution are found in some other lineages, but still others experienced apparently long periods of stasis or very slow evolution. In a single case there is a period of stasis combined with a sudden evolutionary jump as in the punctuated equilibria model.

In the cases of intercontinental dispersal events combined with cladogenesis, where the ancestor in the continent of origin could be identified, the cause of cladogenesis seems to have been geographical isolation. Two tetraconodont lineages were restricted to Eurasia for about 5 Ma. During the Late Miocene, members of these lineages dispersed repeatedly to Africa. The Vallesian is a period of profound climatic changes which are reflected in changes in biogeography of many taxa. It is assumed that these and later climatic changes enabled the dispersal of Tetraconodontinae to Africa.

Structural and topographic relief along the eastern margin of the Rio Grande rift, northern New Mexico, provides a remarkable cross-section through the 26-Ma Questa caldera and cogenetic volcanic and plutonic rocks of the Latir field. Exposed levels increase in depth from mid-Tertiary depositional surfaces in northern parts of the igneous complex to plutonic rocks originally at 3–5 km depths in the S. Erosional remnants of an ash-flow sheet of weakly peralkaline rhyolite (Amalia Tuff) and andesitic to dacitic precursor lavas, disrupted by rift-related faults, are preserved as far as 45 km beyond their sources at the Questa caldera. Broadly comagmatic 26 Ma batholithic granitic rocks, exposed over an area of 20 by 35 km, range from mesozonal granodiorite to epizonal porphyritic granite and aplite; shallower and more silicic phases are mostly within the caldera. Compositionally and texturally distinct granites define resurgent intrusions within the caldera and discontinuous ring dikes along its margins; a batholithic mass of granodiorite extends 20 km S of the caldera and locally grades vertically to granite below its flat-lying roof. A negative Bouguer gravity anomaly (15–20 mgal), which encloses exposed granitic rocks and coincides with boundaries of the Questa caldera, defines boundaries of the shallow batholith, emplaced low in the volcanic sequence and in underlying Precambrian rocks. Palaeomagnetic pole positions indicate that successively crystallised granitic plutons cooled through Curie temperatures during the time of caldera formation, initial regional extension, and rotational tilting of the volcanic rocks. Isotopic ages for most intrusions are indistinguishable from the volcanic rocks. These relations indicate that the batholithic complex broadly represents the source magma for the volcanic rocks, into which the Questa caldera collapsed, and that the magma was largely liquid during regional tectonic disruption.

Volcanic and plutonic magmas (1) changed from early high-K calc-alkaline to alkalic prior to caldera eruptions; (2) differentiated to a weakly peralkaline rhyolite and equivalent acmiteartvedsonite granite cap (underlain by calc-alkaline granite) when the caldera formed at 26·5 Ma; then (3) reverted to calc-alkaline compositions. Concentrations of alkalis and minor elements such as Rb, Th, U, Nb, Zr, and Y reached maxima at the caldera stage. The volcanic rocks constitute intermittently quenched samples of upper parts of Questa magma bodies at early stages of crystallisation; in contrast, the comagmatic granitic rocks preserve an integrated record of protracted crystallisation of the magmatic residue as eruptions diminished. Multiple differentiation processes were active during evolution of the Questa magmatic system: crystal fractionation, replenishment by mantle and lower crustal melts of varying chemical and isotopic character, mixing of evolved with more primitive magmas, upper crustal assimilation, and perhaps volatile-transfer processes. As a result, an evolving batholithic cluster of coalesced magma chambers generated diverse assemblages of broadly cogenetic rocks within a few million years. Evolution of the Questa magmatic system and similar high-level Tertiary granitic batholiths nearby in the southern Rocky Mountains provides broad insights into magmatic processes in continental regions such as the overall shapes of batholiths, time and compositional relations between cogenetic volcanic and plutonic rocks, density equilibration of magmas with country rocks, and thermal evolution of continental crust.

These notes on Arctic Tardigrada embody the results of an examination of quantities of moss collected by Mr William S. Bruce on his various expeditions to the Arctic Regions.

While studying the Tardigrada of the Scottish lochs, I wished to compare our Tardigrade fauna with that of more northern lands, as it was thought that, considering the geographical position of Scotland, its fauna might have some relation with that of those lands. Mr Bruce was kind enough to put all his available material at my disposal.

Our district (Pl. II) includes an exceptionally beautiful tract of the Highlands, stretching from the Errochty Water, half a dozen miles north-east of Kinloch Rannoch, to near Loch Tay. It reaches its greatest height in Beinn a' Chuallaich (2925 ft.), Schiehallion (3547 ft.), Carn Mairg (3419 ft.), and Carn Gorm (CG, Pl. II, 3370 ft.). These, with companion mountains that closely approach the 3000-foot contour, are remnants of the much dissected Highland plateau. There are two main eastwardly-draining valley systems: the more northerly holds Loch Rannoch and the River Tummel; the more southerly is known throughout its length as Glen Lyon. The southern limit of the district approximately follows the divide between Glen Lyon and Loch Tay, but fails to include the summit of Ben Lawers (3984 ft.) (inset, text-fig. 14). The eastern margin is really marked by the great Loch Tay fault; though, for purposes of comparison, some previously published mapping is reproduced on PL II east of this fault. The Tummel and the Lyon cross the Loch Tay fault at about 450 and 400 ft. above sea-level.

Drepanophycus spinaeformis Göppert is a long ranging Devonian plant. Although reported from numerous localities, it is far from well understood. Observations on specimens from the Emsian Strathmore Group of Scotland have revealed variation in forms of branching including root-like axes on branches interpreted as rhizomes. The anatomy of the xylem is described from uncompressed pyrite permineralisations. Cuticle characteristics are also described and discussed. The systematic position of the plant is debated since, although the morphology of the leaves, leaf traces, roots and xylem indicate an affinity with the lycopods, there is some doubt as to whether sporangial position permits inclusion in this group.

In 1905 there was published an account of the Tardigrada collected in the Scottish Lochs by the Lake Survey (6). At that date we were able to name 21 species. The subsequent work of the Survey has enabled us to add a number of species to the list.

Moreover, the wanderings of the members of the Survey over every part of Scotland offered an excellent opportunity for the study of the whole Tardigrade Fauna. A recent journey to the Orkney and Shetland Islands added much of interest to our knowledge of Tardigrada, though few of the species found were lacustrine. The work of Mr Wm. Evans in the basin of the Forth has also added much of value to our records of Tardigrada (7), (10).