Small disc-shaped bodies have frequently been noticed in coal and the accompanying shales. Specimens were figured by Mr. Prestwich in 1840, in his paper on the Geology of Coalbrook Dale (Geol. Trans., Second Series, vol. v., tab. xxxviii., ff. 8, 8a); and Professor Morris, who described Mr. Prestwich's fossils, characterises them as ‘capsules’ of his Lepidodendron longibracteatum. But it does not appear from either the illustrations of the two spikes of his species, or from the letter-press, that he had found the capsules associated with the reniform thecæ of the spikes. Prof. Balfour has also figured and described similar bodies in a paper read before the Royal Society of Edinburgh in 1854. He found them in the ‘splint-coal’ of Fordel, near Inverkeithing, in Fife. He says, ‘Besides Sigillarias and Stigmarias, we also detect in the Fordel Coal peculiar rounded organisms which have the appearance of seeds. Dr. Fleming informs me that similar bodies have been observed by him in coal, and that he exhibited them to Mr. Witham about twenty years ago. They have also been seen by Dr. Fleming in Lochgelly and Arniston “parrot,” and in the coal at Boghead; and from having observed them in “cherry,” “splint,” and “cannel” coals, he is disposed to consider them as a somewhat common feature. I have seen them in coal from Miller Hill, near Dalkeith, as well as in the coalfrom Fife. They appear to be certainly allied to the fructification of the Lycopodiaceæ of the present day, more particularly to that form of it which consists of two valves placed in apposition and containing what is called Lycopode-powder. Theae and like bodies I, therefore, consider to be the sporangia or spore-cases of some plant allied to Lycopodium, perhaps Sigillaria. The valves present under the microscope a reticulated surface, and minute granular matter seems to be attached to the inner surface.’—(Edin. Trans., vol. xxi. p. 191).

Dolerite dykes in the East Finnmark Scandinavian Caledonides form three geochemical suites: Digermulhalvøya–Magerøya – WNW–ESE-trending, c. 337–332 Ma, possibly also c. 293 Ma, continental within-plate; East Varangerhalvøya – NE–SW and N–S, c. 376 Ma, continental plate-margin; Styret – NE–SW, also c. 376 Ma, chemically intermediate to the other two groups. New K–Ar data from metadolerites on Varangerhalvøya give a 7-point ‘lower envelope’ isochron of 577 ± 14 Ma (MSWD 1.04). This is concordant with a published upper intercept U–Pb zircon age (567+30−23 Ma) from an East Varangerhalvøya dolerite, here re-interpreted to reflect Neoproterozoic basement fracturing contemporaneous with the emplacement of the metadolerites. Intrusion of the younger dolerites at c. 376 Ma reactivated this trend, and may be responsible for the published zircon lower intercept age of 392+25−36 Ma. Clarification of the intrusion and structural chronology, integrated with extensive new geochemical data, enables a better understanding of the evolution of this part of the Scandinavian Caledonides.

A north-easterly palaeoslope is demonstrated for the south-eastern Scottish Borders during the Upper Devonian. Alkali basalt extrusion in the (?basal) Tournaisian was followed by initiation of the Northumberland basin as a structural feature. Basin subsidence gave rise to a south-easterly palaeoslope in the Southern Uplands and was coincident with the mid-Tournaisian marine transgression.

The asymmetry of the continental margin around southern Africa can be related to Mesozoic sediment thicknesses, which were in turn controlled by the local structural setting. On the west coast, the Orange Basin sediments were built out as a thick wedge over the margin of the continent by discharge from the Orange River, whereas on the Agulhas Bank, sedimentation was confined to continental areas. Off the east coast the extremely narrow margin of the continent did not form an effective trap for sediments, which were readily carried beyond it. Cainozoic sediments are thin, and modify the Mesozoic sediment pile only locally on the outer shelf and slope.

The first part of the “Records of the Geological Survey of India” for 1879 contains some interesting notes by Mr. R. Lydekker, B.A., descriptive of a “few fragmentary bird-remains” recently obtained from the Tertiary deposits of the Siwaliks, and preserved in the Geological Museum at Calcutta. The subjects of most interest alluded to in this memoir are some bones referred to Dromœus, by Mr. Lydekker, and his remarks thereon, and upon some bones of kindred birds which form part of the extensive series of vertebrate remains collected in the same range of hills by the late Colonel Sir Proby T. Cautley, then Captain in the Bengal Artillery, and presented by him to the National Collection.

Feldspathoidal and quartz-bearing syenite xenoliths in c. 235 to 155 ka tuffs surrounding the Latera caldera have textures and mineral assemblages that indicate an origin from the crystalline margins of a shallow magma chamber. This lithic suite exhibits a diversity of plutonic fabrics; unaltered, glass-bearing nodules with undeformed sanidine frameworks coexist with completely crystallized clasts, many of which show evidence of subsolidus modification. The syenites comprise eutectic mineral assemblages with high percentages of titanite, apatite, and melanite garnet as accessory minerals. Ubiquitous reaction textures in syenite accompany progressive changes in mineral assemblages, and they show the decreasing influence of limestone contamination with distance from the contact of syenite and skarn wallrock. Diagnostic mineral assemblages include nepheline rich in calcite inclusions, coexisting titanite and metamorphic perovskite, zircon with baddeleyite inclusions, fluorapatite mantled by a possible carbonate-bearing apatite (francolite), melanite garnet intergrown with clinopyroxene, and interstitial haüyne rich in pyrrhotite inclusions.

At Latera, pumice fragments in the same deposit can exhibit up to ten-fold differences in vesicularity and crystal content (from < 5 to > 50 vol. % phenocrysts). These clasts, in conjunction with glass-bearing syenite and skarn xenoliths, may represent a range of progressively crystallized magmas that were quenched at the instant of their eruptive entrainment. The major element abundances of pumices and syenite reflect the fractionation of plagioclase and sanidine, with lesser amounts of fassaitic diopside, leucite, biotite, apatite, and alkali amphibole. Trace element ratios (e.g. Rb/Sr, Nb/Ta, Zr/Hf, LREE/HREE), on the other hand, are highly variable for crystalline and pumiceous ejecta, and some element variations (e.g. Li, Ta, Nb, Th) cannot be entirely reconciled with simple crystal-liquid fractionation. The syenite clasts span a range of compositions from strongly fractionated assemblages rich in accessory minerals to compositions that more closely approximate quenched reservoir liquids. These features reflect processes that range from pure fractional crystallization to in situ crystallization where fractionated liquid was trapped in the pores of sidewall cumulates along the chamber roof and walls.

Carriacou, the largest of the Grenadines lying between Grenada and St. Vincent, is the only one, so far as is known, of that group of islands which is not predominantly volcanic in origin. It may be described as the only limestone, or largely limestone, island in the whole inner arc of the Lesser Antilles which comprises Grenada, the Grenadines, St. Lucia, Martinique, Guadeloupe (west half), Montserrat, Nevis, St. Kitts, St. Eustatius, and Saba. Carriacou is 6¾ miles long and 2⅓ in greatest width and at High North Hill and Chapeau Carré rises to 980 and 960 feet. The remainder of the island is rugged and has several lesser peaks and a central ridge, running roughly north to south, 600–830 feet in height.

Five bodies with either visible or inferred mineral zoning occur in the serpentinite mass in Glen Urquhart. Their mineralogy and petrology suggest a hydrothermal origin, and they are grouped with other hydrothermal injection phenomena in the glen thought go be phases of Older Granite activity. The two northern bodies seem clearly similar to simple vein deposits characterized by albitite without excess alumina (corundum). The origin of the remaining three bodies is discussed and the view that they too are deposits of albitite-type is favoured. They lack an exposed albitite zone, but this does not invalidate the comparison. Albitite deposits, it is suggested, originate where moving hydrothermal solutions from granites cut ultrabasic rocks. This origin for the veins is preferred to Larsen's (1928) suggestion that the hydrothermal veins represent late-stage sodic residual liquids left after the crystallization of most of the material of “ ultrabasic magmas ”.

A thick succession of continental redbeds was deposited in a 50 km wide intra-arc basin on the Andean active continental margin in the Atacama region of northern Chile during early Cretaceous times. Upper Jurassic to early Cretaceous marine limestones were buried by the seaward progradation of a succession of coastal dunes, saline lakes and sandflats. Aeolian dune fields migrating towards the east across these coastal plains became stabilized by the growth of vegetation. Interdune alluvial areas between the sand dunes and dune fields developed into extensive alluvial braid plains which were in turn superimposed by alluvial fans. These fans were inundated by a regionally extensive saline lake produced by tectonic or volcanic damming of the sedimentary basin. This lake dried up leaving a large area of playa-lake mudflats. The climate was warm and semi-arid with a low and seasonal rainfall. Parts of the area supported a substantial vegetation of woody plants, together with a vertebrate fauna of dinosaurs, pterosaurs and crocodiles. The continental redbeds were derived from a volcanic source and were deposited on continental crust in a deep but narrow, north-south elongated, fault-bounded graben. This extensional basin formed in an intra-arc setting within an active andesitic volcanic chain. Upwards-coarsening sedimentary successions were the product of uplift of the fault-bounded margins of the basin.

In Professor Henry Drummond's “Tropical Africa,” 8vo. London, 1888, pp. 183–199 are occupied with an interesting “Geological Sketch” of the country between the Zambesi River (about 18° S. Lat.) and the Tanganyika plateau (about 3° S. Lat.), his own observations having been made along a route from Kilimane on the coast, to the Shiré, and up that river, by Lake Shirwa and Lake Nyassa, to Karonga (or Karonga's village) on the north west shore near the end of the lake; and thence through the Uchungu district, for about 70 miles, in a part of the Tanganyika plateau.

In 1896 I described some decapod Crustaceans found in the Cretaceous formation of Vancouver and adjacent islands, British Columbia, which, with the approval of Dr. G. M. Dawson, C.M.G., F.R.S., the Director, had been most kindly placed in my hands for examination by Dr. J. F. Whiteaves, F.G.S., Palæontologist to the Geological Survey of Canada. They were referred by me to the genera Callianassa, Homolopsis, Palæocorystes, and Plagiolophus (see Quart. Journ. Geol. Soc., 1896, vol. lii, pp. 221–228, with 6 figures).

The Quartz-dolerite intrusion of Sgùrr nam Meann, Ardnamurchan, is shown to be a ring-dyke which has sill apophyses extending from its outer wall. This is a form of intrusion which has not been recognized before, and its field relations are described in detail. The quartz-dolerite is extensively veined by acid rocks which are ubiquitous in all parts of the intrusion, and most abundant in the sills. From the evidence of the distribution and nature of the veining it is concluded that the acid and basic components of the intrusion must have been ernplaced simultaneously. It is suggested that a gas-charged, acid residual magma may have separated from a crystallizing basic parent under the influence of sudden reductions of external pressure acting upon the system.

The two admirable summaries of our knowledge of fossil Crocodilia recently published by Mr. A. Smith Woodward—the one relating to British forms, in this Magazine, and the other, comprising the whole order, in the “Proceedings of the Geologists' Association”—render it a comparatively easy matter to find out what is known concerning any particular species or genus; and I may accordingly at once proceed to the proper subject of this paper.

The present paper is a continuation of that published in the Geological Magazine, vol LXII, NO. IV, April, 1925 PP.145–80.

All bentonite and bentonite-resembling layers thicker than a few millimetres from a 120m-thick Early Silurian sequence on Gotland, Sweden, were searched for shocked quartz grains of comet or asteroid impact origin. Although more than 200000 quartz grains from 86 bentonite samples were studied, not one single grain with multiple planar shock features was found. The studied sequence represents sedimentation during a period of about 2 million years. Impact frequencies, estimated from the cratering record and astronomical observations, indicate that during a 2-myr- period on average 20 comet or asteroid bodies larger than 0.5 km in diameter strike the Earth. The number of smaller impacting bodies is many times higher. In the light of this high frequency of impacts, the absence of any shocked-quartz-bearing fallout layer in our sequence indicates that lateral spreading of such ejecta is relatively restricted during small- and medium-scale impact events.

The results also show that shocked quartz in general is absent or extremely rare in volcanic ash. This strengthens the case for an impact-related origin of shocked quartz grains in the Cretaceous–Tertiary boundary days.

The type specimen of Regnosaurus northamptoni Mantell, a partial right mandible, is redescribed and compared with a wide variety of dinosaurian taxa. We suggest that Regnosaurusis not an ankylosaur or a sauropod as previously thought, but represents the fragmentary remains of a ‘primitive’ stegosaur. Regnosaurus and Huayangosaurus share two derived characters, suggesting that these two genera should be provisionally regarded as sister taxa. The implications of these findings for stegosaur evolution and biogeography are discussed briefly.

Two-dimensional flexural backstripping and thermal modelling (assuming laterally variable stretching) is applied along regional depth-converted interpreted seismic profiles from the Laxmi Basin in the Arabian Sea. Results from reverse post-rift flexural modelling reveal considerable basin-wide subsidence in response to the crustal geodynamics during and after the last extensional phase. Unloading of the stratigraphy allows us to estimate the degree of laterally varying extension, assuming thermal subsidence and pure shear. High degrees of extension in the basin centre predict considerable water depths at the time of rift cessation, consistent with deep drilling data. We suggest that regional extension prior to Paleocene time could have fuelled variable subsidence in the Laxmi Basin but that extension is less than seen in typical oceanic lithosphere. Volcanic loading by the seamounts shortly after extension has flexed the basin and implies an effective elastic thickness (Te) at that time of ∼6 km. Reconstruction of the seamount top near sea level at the end of emplacement indicates no major transient uplift potentially linked to the Deccan mantle plume activity. Backstripping of post-rift sediments from interpreted seismic profiles supports the presence of a hyper-thinned crust underneath the Laxmi Basin, with β factors reaching >7 in the basin centre and ∼3 across much of the basin width. Computations of decompacted sediment accumulation rates in light of new results from IODP Expedition 355 show that basin sedimentation peaked during early–middle Miocene time, possibly coeval with uplift and erosion of the Himalayan–Tibetan Plateau driven by strong summer monsoon rains.

Two strikingly different successions of Lower Carboniferous (mainly Tournaisian) sedimentary rocks are closely juxtaposed on the NE coast of the island of Arran, SW Scotland. Near the village of Corrie a thin succession (~ 17 m) of Tournaisian rocks is preserved, whereas in the neighbouring Fallen Rocks–Laggan area, correlative rocks are > 300 m in thickness. These contrasting successions are separated by the Laggan Fault, which is a landward extension of the submarine Brodick Bay Fault, marking the SW boundary of the Northeast Arran Trough. The contrasting thickness and stratigraphy of the two sequences of sedimentary rocks result from juxtaposition of shoulder and trough deposits along the Laggan–Brodick Bay Fault. Although originally a normal, basin-defining fault, later sinistral movements caused significant displacement of the NE Arran Trough, together with a segment of the Highland Boundary Fault, from their original positions. The most northerly occurrence of the Highland Boundary Fault on Arran is thought to be the truncated northern end of the Corloch Fault. To the SW the surface trace of the Highland Boundary Fault is largely obscured by a Palaeogene granite body but it is present on the west side of the island, near Dougrie. The Highland Boundary Fault appears to be displaced to the south, in Kilbrannan Sound, by a series of NW-trending sinistral transcurrent faults. Thus the ‘anomalous’ trend of the Highland Boundary Fault and narrowing of the Midland Valley of Scotland in the Firth of Clyde area may be explained by later fault movements and intrusion of the Palaeogene North Arran Granite Pluton.