Having frequently visited Upware during the past fourteen months, for the purpose of collecting from the Lower Greensand, in which I have been very successful, having obtained for this Museum a beautiful and choice collection, I have had every opportunity of observing the progress of the excavations, and of noting the relative position of the beds.

In the “Catalogue of Fossil Fishes in the British Museum“ (pt. i. 1889, p. 76, pl. iii. fig. 1), the imperfect rostrum of a Selachian fish from the Upper Cretaceous of Mount Lebanon was described under the new generic and specific name of Sclerorhynchm atavus. Presenting some resemblances to the rostrum both of the typical saw-fish (Prislis) and of PristiopJtorus, hesitation was expressed in determining the systematic position of the genus to which the fossil pertained; but from the apparently complex nature of the rostral cartilages and the absence of extended prepalatines, it was deemed advisable to place the fish provisionally in the family of Pristidæ.

In every correlation exercise the diachroneity of the lithostratigraphic boundaries determines the discrepancy between lithostratigraphic correlation and time-correlation. Here it is shown that diachroneity varies in degree as a simple function of the direction in which correlation is made, and hence that stratigraphic correlation must take that direction into account. When the direction of correlation is not known, a sound strategy for time-correlation of lithostratigraphic boundaries is to assume that each is at its most diachronous.

Whatever may be the precise biological value of this genus or subgenus as distinct from Purpura, it forms a remarkable group, limited, according to our present knowledge, both in time and space. Of the conditions favourable to its development we only obtain glimpses here and there. In the Coral Rag of Yorkshire one would say that the genus displays a remarkable tendency to variability within certain limits, so much so that almost every specimen found in anything like a decent state of preservation differs in some point of ornament: hence the extreme difficulty of specific arrangement. One might almost suppose that, like the Ammonite, the genus having worked out the limits of possible change, flourished within a short period only, and speedily became extinct.

In these notes it is my object to describe and figure some of the more imporant Chalk Polyzoa that have not yet been described, or have been described from material less complete than mine.

The occurrence of two Archæan groups in Shropshire is now well known to geologists. The chain of hills which strikes to the south-west from Lilleshall, north-east of Wellington, to the region south of Church-Stretton, is mainly composed of bedded volcanic rocks; but gneissic and granitoid types have been recognized at the Ercal and at Primrose Hill, the elevations forming the opposite extremities of the Wrekin, and a small exposure was detected near Hope Bowdler, east of Church-Stretton. A second axis of the old rocks, ranging parallel to the Wrekin chain, consists of volcanic ejecta and highly indurated grits, which are probably to be referred to the younger of the two Archæan groups hitherto recognized in the county. The relations between the volcanic and the gneissic systems is clearly defined by the Charlton Hill (see map) conglomerate (a band in the volcanic series), which contains numerous well-rounded pebbles of rock precisely similar to the granitoid gneiss of Primrose Hill. This fact implies a considerable break between the two groups.

The Cheviot district is largely composed of those quartzless porphyritic rocks to which the term porphyrite has been applied both by English and Continental petrologists. The Cheviot porphyrites are characterized by a compact felsitic ground-mass, throughout which are scattered numerous crystals of felspar, mostly belonging to triclinic species. The ground-mass varies in colour; the two principal shades being dark purple and red. These porphyrites are evidently more or less altered rocks and sometimes the alteration has been carried so far as to make it almost, if not quite impossible to recognize their original nature by macroscopic examination. Amygdaloidal varieties are not uncommon, and in these agates are frequently found. In addition to the ordinary porphyrites, there occur masses of volcanic ash and breccia, and also a remarkable rock which has been called pitchstone-porphyrite. This is dark almost black in colour, with a well-marked resinous lustre and a specific gravity lying between 2·53 and 2·62. It is porphyritic in texture; the large crystals consisting of a fresh glassy-looking triclinic felspar. Red veins usually traverse the rock in different directions. The boulders lying in the streams are covered with a thin light-coloured crust due to weathering, but at a distance of a quarter of an inch from the surface, or even less, the fresh unaltered rock is always found.

The Iranian territory is composed of a mosaic of tectonic units, several of which underwent in the Permian and Triassic periods a migration from northern Gondwana to southern Laurussia associated with the opening of the Neo-Tethys Ocean. Although this broad outline of Permo-Triassic palaeogeographical evolution of Iranian microplates is now widely accepted, the individual timing of migration of these blocks, and their biogeographical relationships, remain insufficiently known. Here I review the Late Palaeozoic record of trilobites in Iran and Armenia, and discuss their palaeobiogeographical affinities in an attempt to shed light on the Permian palaeogeographical evolution of Iranian and Armenian terranes. Seven Iranian or Armenian localities, representative of five tectonic units, have yielded Carboniferous and Permian trilobites. Ten species are recognized, including two new taxa, Persia praecox gen. nov. sp. nov. and Pseudophillipsia (s.l.) parvizii sp. nov. P. praecox is the only Carboniferous (Tournaisian) species. The others are Wordian to Wuchiapingian in age and can be separated into three morphological groups, probably representing clades. One is composed of representatives of Acropyge, while the two others (armenica-group and paffenholzi-group) comprise species of Pseudophillipsia. Only P. (s.l.) parvizii sp. nov. from the Zagros Mountains (Arabian Plate) is not attributed to one of these groups. The distribution of trilobites in Iran and Armenia strongly suggests that the Alborz, Central Iran and Transcaucasia microplates represented a single biogeographical unit in Middle and Late Permian times. Special relationships of this biochore with South China can also be stressed.

The collections described by Mr. Spath were made during Sir Martin Conway's Expedition across Spitsbergen in 1896, and include also those then collected by Professor Garwood and presented by him to the British Museum of Natural History.

High-pressure low-temperature metamorphic sediments of the Phyllite–Quartzite unit sensu stricto and the Talea Ori group are investigated in the field, microstructurally and by U–Pb dating of detrital zircons to shed light on their palaeogeographic origin. Zircon age spectra with ages >450 Ma of the Phyllite–Quartzite unit sensu stricto indicate a palaeogeographic origin at the northern margin of East Gondwana. In contrast, the lower stratigraphic, siliciclastic formations of the Talea Ori group show a high number of well-rounded Cambrian to Early Carboniferous aged zircons and a Neoproterozoic zircon age spectrum with East Gondwana affinity. Based on the comparison of zircon age data, a possible distal sediment source is the Sakarya Zone at the southern active margin of Eurasia. To reconcile the zircon data with the geological observations we propose different alternative models, or a combination of these, including sediment transport from the Sakarya Zone and/or a westerly source towards the northern margin of Gondwana as well as terrane-displacement of the Sakarya Zone. Also, a palaeogeographic origin of the Talea Ori group at the southern active margin of Eurasia cannot be excluded. This alternative, however, would not be consistent with the usually assumed association of the Talea Ori group with the Plattenkalk unit characterized by a palaeogeographic origin at the northern margin of Gondwana.

Efficient extraction of oxygen from ambient waters played a critical role in the development of early arthropods. Maximizing gill surface area enhanced oxygen uptake ability but, with gills necessarily exposed to the external environment, also presented the issue of gill contamination. Here we document setae inserted on the dorsal surface of walking legs of the benthic-dwelling middle Cambrian Olenoides serratus and on the gill shaft of the Late Ordovician Triarthrus eatoni. Based on their physical positions relative to gill filaments, we interpret these setae to have been used to groom the gills, removing particles trapped among the filaments. The coordination between setae and gill filaments is comparable to that seen among modern crustaceans, which use a diverse set of setae-bearing appendages to penetrate between gill filaments when grooming. Grooming is known relatively early in trilobite evolutionary history and would have enhanced gill efficiency by maximizing the surface area for oxygen uptake.

The Terceira Rift is a subsidiary zone of crustal generation in the Azores to the E of the Mid-Atlantic Ridge. The geology of the island of Terceira, which straddles the rift, is thought to give an indication of the nature of the volcanic activity along this zone of crustal separation. Terceira is composed of 4 large strato-volcanoes associated with trachytic or trachybasaltic activity which have since been intruded by basaltic magmas to form monogenic cinder cones and lava flows on the flanks of these large volcanoes. There is little direct evidence of eruptions along fissures although lines of cinder cones may indicate zones of weakness in the crust.

In the extreme northernmost part of Canada, lying between North Latitudes 56° and 68° and West Longitudes 88° and 112°, is an area of about 400,000 square miles, which had up to the past two years remained geologically unexplored.

In 1892 the Director of the Geological Survey of Canada sent the writer to explore the country north of Churchill River, and south-west of Lake Athabasca;in1893 the exploration was continued northward, along the north shore of Athabasca Lake

The use of the term mugearite as a synonym for oligoclase-basalt is discussed. It is shown that the two rock-types, though often agreeing closely in chemical composition, may differ appreciably in their fabric and mineralogy.