A diverse, previously undescribed trilobite fauna from northwest Iran sheds new light on the Early Palaeozoic geography of the Alborz terrane. The structural history of the Alborz region is well known, though faunal data for the area are sparse, especially for the Ordovician. Trilobites, brachiopods, conodonts, bryozoans and echinoderms occur in a red grainstone/packstone near the village of Tatavrud, 35 km southwest of Bandar-e-Anzali. The fossils indicate a Late Ordovician age, although lithologically similar outcrops in northern Iran have previously been considered Silurian. Trilobite genera occurring include Trinodus, Geragnostus, Illaenus, Panderia, Phorocephala, Ovalocephalus, Dicranopeltis, Symphysops, Cyclopyge, and Sphaerexochus. Similar assemblages have been reported from the Late Ordovician of Ireland, Spain, Poland, Norway, northwest China, Kazakhstan and the Turkistan–Alai Ridge (Uzbekistan–Kyrgyzstan border). Reconstructions of Late Ordovician geography place the Alborz terrane near the eastern margin of Gondwana, but there is doubt as to its precise location. Some workers have considered it part of the margin while others have considered it a separate terrane. Several species present, including Mezzaluna tatavrudensis n. sp. and Phorocephala cf. ulugtana (Petrunina, 1975) are very similar to taxa described from the Turkistan–Alai Ridge. In addition, the isocolid genus Paratiresias has only been reported from Iran, the Turkistan–Alai Ridge and northwest China. The presence of these taxa indicates that the Alborz terrane was in close proximity to the eastern margin of Gondwana at this time.

Raasay, one of the major islands of the Inner Hebrides, lies between the Isle of Skye, from which it is separated by the Sound of Raasay, on the west, and the mainland district of Applecross on the east. From Rudha na Cloiche, the southernmost promontory, to Rudha nan Sgarbh in the extreme north, the island has a length of over 13 miles, while the breadth from west to east varies from 3 miles near Ósgaig to a ½ mile just south of Arnish or at An Caol. The total surface area is about 27 square miles. The island is separated from Rona on the north by Caol Rònach, studded with islets and submerged rocks, a little more than a mile wide.

Osteohistological characteristics of the large temnospondyl amphibian Metoposaurus diagnosticus from the Upper Triassic of Poland (Krasiejów locality) were determined using vertebral intercentra thin-sections from different regions and growth stages. The intercentra showed a trabecular structure in both the endochondral and periosteal domains. Endochondral ossification developed first, and the primary bone occurs near the periphery with a higher degree of remodelling in the centre. Periosteal bone deposition begins later; first on the ventral side, continuing laterally and finally onto the dorsal side. Periosteal growth rate was initially very rapid, and then subsequently decreased in rate. In all sections, numerous remains of calcified cartilage are visible, which may indicate a juvenile, paedomorphic or plesiomorphic character. The four histologic ontogenetic stages (HOS) of sampled vertebrae were determined based on growth marks. Most of the sampled bones belong to juvenile individuals (HOS 1 to 3), apart from one atlas and the largest anterior dorsal intercentrum, which represent the oldest described stage (HOS 4). Sharpey's fibres are preserved in ventro-lateral cortical regions, around parapophyses and on the posterior side of the neural arch.

Self-organised criticality of the crust appears to make deterministic earthquake prediction of time, place and magnitude of individual large earthquakes inherently impossible. This closes one line of approach to mitigating earthquake hazards. This paper suggests that a viable alternative to earthquake prediction is monitoring the build-up of stress before a large earthquake can occur. A new understanding of rock deformation allows stress changes to be monitored with seismic shear-wave splitting (seismic birefringence). With a suitable monitoring installation, this would allow the stochastic proximity of impending earthquakes to be recognised so that earthquakes could be forecast in the sense of recognising that crustal deformation was preparing for a large earthquake. Such stress-forecasting is not prediction, but, in many circumstances, a possible forecast crescendo of increasing urgency is exactly what is needed to best mitigate hazard to life and property.

The arctolepid fish “Phlyctœnaspis” germanica is redescribed as Stuertzaspis n.gen. An interpretation of the head shield is attempted and it is suggested on this evidence that the fish is a relatively unspecialized member of Denison's subfamily Actinolepinæ. On the ventral surface of the fossil is preserved the postethmo-occipital ossification of the neural endocranium, a structure previously satisfactorily known only in Kujdanowiaspis among the Arctolepida. Generally the endocranium of Stuertzaspis is similar to that of Kujdanowiaspis, although it shows some interesting differences, particularly in the orbital and occipital regions.

The postcranial skeleton of the seymouriamorph Utegenia shpinari (?Upper Carboniferous–Lower Permian, Kurgalin Formation, Kazakhstan) is redescribed. Features that distinguish it from other Lower Permian seymouriamorphs (Discosauriscus, Ariekanerpeton, Seymouria) are: broad anterior portion of the interclavicle stem, merging indistinctly into the interclavicle plate; absence of a bulge in the anterior half of such a stem; presence of at least 28 presacral vertebrae; gastralia. The poorly ossified limbs of the largest Utegenia specimens are similar in degree of development to those of larval Discosauriscus, but the almost cylindrical, anterior trunk pleurocentra recall the condition of early juvenile Discosauriscus. A phylogeny of the best known seymouriamorphs, using a small but diverse exemplar from other early tetrapod groups, places Utegenia within seymouriamorphs as sister taxon to discosauriscids (Ariekanerpeton plus Discosauriscus). This conclusion affects origin and dispersal scenarios for seymouriamorphs, and supports the hypothesis of a widespread geographical record of Lower Permian taxa spanning across western Euramerica and eastern Asia.

The first part (5) of a study of the quantitative distribution of the bottom-fauna in Scottish waters, and of the natural faunistic divisions of the North Sea and adjacent areas, dealt with the distribution of the molluscs in the North Sea. In this paper the echinoderms from the same area are treated on similar lines. In addition the natural faunistic divisions, as shown by the distribution of the dominant species of molluscs and echinoderms, and the validity of Petersen's community concept as applied to the North Sea, are discussed.

Reference should be made to the earlier paper for information concerning the methods of collecting, the area covered by the Scottish surveys, similar surveys carried out by other workers in the remaining parts of the North Sea, the number of hauls in each square, and other introductory matters.

The Western or Toro-Ankole volcanic province of Uganda consists of several areas of tuffs, explosion craters, and rare lava flows situated to the east and south-east of Ruwenzori (text-fig. 1). From north to south these volcanic fields are distinguished under the names (a) Rusekere; (b) Fort Portal; (c) Ndale, formerly known as the “Kyatwa area”; (d) Katwe-Kikorongo; (e) Bunyaruguru, formerly known as the “Kichwamba area”; and (f) Katunga. The Bunyaruguru field extends southwards from Lake George in and adjacent to the north-eastern portion of the Lake Edward section of the western rift. The Kabirenge and Lyakauli lavas (text-fig. 2) occur on the eastern edge of the rift depression immediately north-west of Nyondo crater (E. 30° 04′ 25″; S. 0° 14′ 30″). As a group, they constitute one of the four lava occurrences now known in Bunyaruguru, the other three being those of Chamengo, Mafuru, and Kazimiro (text-fig. 2). Otherwise, lava occurs only as fragments and lumps in the tuffs and as bombs and ejected blocks. The Kabirenge-Lyakauli lavas are also of special interest because, as described later by Professor Holmes, they consist of various members of the mafurite series, characterised by the presence of the recently discovered mineral kalsilite, a polymorph of KAlSiO4.

§ 1. A short description of some temperature observations in the Madüsee has been published in the Scottish Geographical Magazine for December 1910, and this communication aims at giving a more complete description of the observations with a first attempt at the mathematical discussion of oscillations at the surface of separation of two liquids in a basin of varying depth and cross-section.

The fossils dealt with in this part of our memoir should have been included in the first paper of the series had it been possible to treat the plants described in the order of the complexity of their structure. Unfortunately, however, the specimens did not reach our hands until Part I. was already published; and since we were no longer able to place them in their proper position in the sequence already embarked upon, it was decided to defer their treatment until the conclusion of the memoir.

Many of the earlier accounts of the group of Crustacea, known as Isopoda, suffer from want of more detailed diagnoses and figures. To some extent this has been remedied during recent years by the authors of different monographs, but there are still many families which remain somewhat obscure, or only partially understood, owing to the above-mentioned cause. Such a family is the Idoteidæ.

In the present communication I propose to revise the diagnoses of the British genera and species, to set forth in greater detail than has hitherto been done their structure, illustrating the same, and to discuss the classification and affinities of the family as a whole.

Triarthrinid trilobites are described from the Middle Ordovician Andersön Shale and Örån Shale of Jämtland, central Sweden. The faunas include at least five species, belonging to two genera, Porterfieldia Cooper 1953 and Triarthrus Green 1832. Porterfieldia is represented by a single species, Porterfieldia humilis (Hadding 1913), while at least four species belong to Triarthrus: T. freji Thorslund, 1940, T. jemtlandicus Linnarsson, 1875, T. latissimus nom. nov. and T. linnarssoni Thorslund, 1940. P. humilis is found only in the lower Andersön Shale, equivalent to the Hustedograptus teretiusculus Zone. T. freji, T. jemtlandicus and T. latissimus occur frequently in the upper part of the Anderson Shale, which comprises the Nemagraptus gracilis Zone, and probably also the lower part of the Diplograptus multidens Zone. T. linnarssoni occurs throughout the Örån Shale (mainly Dicranograptus clingani Zone). T. jemtlandicus and T. aff. linnarssoni are also sporadically present in the lower and middle parts of the Oran Shale. Almost all growth stages of T. latissimus, from the anaprotaspid stage and onwards, are represented and the ontogeny is described. The early stages are, however, comparatively uncommon.

While collecting specimens of Diplolabis römeri (Solms) at Pettycur about three years ago, I discovered several blocks of stone containing numerous petrified fragments of another Zygopterid fern—Metaclepsydropsis duplex (Williamson). Two of the blocks were found to be parts of one large mass, and the petrifactions could be traced from the one block into the other. In size the complete mass must have been about 3 feet × 2 feet × 2 feet. The larger portion had to be broken into two before it was possible to remove it. Another block containing similar specimens was obtained later, but the preservation was so poor that the whole of the material was discarded.

The economic importance of the leaf-roll disease of potatoes has been recognised for a number of years owing to the fact that its incidence leads to a heavy reduction in marketable ware. The annual loss to potato growers in England and on the Continent from leaf-roll amounts to a high figure, but the disease is not of such prime importance to the Scottish cultivator as certain other diseases of the virus class to which the potato is prone, namely, mosaic and crinkle.

1. The method for the solution of questions in the theory of probabilities applied in this paper, is that which was developed by the author in a treatise entitled, “An Investigation of the Laws of Thought, on which are founded the Mathematical Theories of Logic and Probabilities.” The practical object of the paper is to deduce from that method certain conclusions relating to the combination of testimonies or judgments. Beside this, however, it will have a speculative reference to some more general questions connected with the theory of probabilities; and especially to the following question, viz.: To what extent the different modes in which the human mind proceeds, in the estimation of probability, may be considered as mutually confirming each other,—as manifestations of a central unity of thought amid the diversity of the forms in which that unity is developed.

The exact horizon occupied by the Shetland strata of Old Red Sandstone age, and their relation to the corresponding series in the north of Scotland, have long been subjects of considerable speculation and much uncertainty. While their resemblance to the flag-stones of Caithness and Orkney was generally recognised, more definite palæontological evidence was required for correlation purposes, and the barrenness of the islands in this respect has been commented on again and again. Up to quite recent years the only fossils found in Shetland were fragmentary plant remains of doubtful affinities, and the small crustacean Estheria membranacea; the abundant ichthyolites which characterise the beds of Caithness and Orkney seemed here to be wanting, and the dearth of fossil evidence is reflected in the conservative and guarded opinions as to the position to be assigned to the series.

Although only about 20m thick, the Andersö Shale contains one of the most diverse, if not the most diverse, late Middle-early Late Ordovician faunas known in Baltoscandia. It includes more than 20 trilobite species, more than 20 species of other shelly fossils, about 10 graptolite species, and about 20 conodont species. Based on its lithology, its geographical position near the foreland basin margin, and the presence of trilobites of the raphiophorid association and conodonts of the Periodon-Pygodus biofacies, this formation is interpreted to represent an outer shelf-upper slope (ramp) deposit laid down in moderately deep water. The co-occurrence of some widespread and biostratigraphically diagnostic conodonts, graptolites and trilobites makes it possible directly to compare distribution patterns of these fossils, establish ties between graptolite and conodont zones, and correlate the formation with units elsewhere in Europe, North America and China. Stratigraphically and faunally, the Andersö Shale is of particular interest in straddling the Middle-Upper Ordovician Series boundary as this boundary is recognised in the new global classification of the Ordovician System.

Rare remains of tyrannosauroid dinosaurs from the Aguja Formation in West Texas indicate the presence here of a relatively gracile species, comparable in form and adult size to Appalachiosaurus or subadult albertosaurines, Gorgosaurus and Albertosaurus. Histologic analysis of one of the specimens indicates that the Aguja tyrannosaur attained an adult size substantially smaller than adult albertosaurines (700 kg, 6·5 m body length). The frontal bone is narrow with a wide orbital slot and a bipartite joint for the postorbital, features thought to be diagnostic of Albertosaurinae; but there is a tall sagittal crest and reduced parietal wedge separating the frontals on the midline, features thought to be diagnostic of Tyrannosaurinae. The tall sagittal crest may be a synapomorphy of Tyrannosaurinae, and the Aguja tyrannosaur is herein referred to that clade. However, the unique combination of character states exhibited by the frontal prevents confident attribution to any known species. The Aguja tyrannosaur provides further evidence that North American Campanian tyrannosauroids were remarkably diverse for such large predators, and that each species was apparently endemic to a relatively small geographic province.

The investigations recorded in the present paper have been carried out at various times during the last six years. A number of the observations on aquatic Oligochæta were made some time ago in India, and, along with some of the theoretical conclusions, formed Part IV. of a Thesis (“Studies on the Aquatic Oligochæta of the Punjab”) presented in 1909 for the D.Sc. degree of the London University. This division of the paper has been considerably extended as a result of further investigations on Indian freshwater forms, and on the littoral Oligochæta of the Clyde, the latter carried out at Millport in 1909. The portion of the present paper which is concerned with the Polychæta and smaller groups represents work done in 1909 at Millport, and in 1912, during my occupancy of the London University table, at the Plymouth Laboratory.

The ensuing paper forms part of a series of researches respecting the consequences of an hypothesis called that of Molecular Vortices, the object of which is to deduce the laws of elasticity, and of heat as connected with elasticity, by means of the principles of mechanics, from a physical supposition consistent and connected with the theory which deduces the laws of radiant light and heat from the hypothesis of undulations. Those researches were commenced in 1842, and after having been laid aside for nearly seven years, from the want of experimental data, were resumed in consequence of the appearance of the experiments of M. Regnault on gases and vapours.

The investigation which I have now to describe, relates to the mutual conversion of heat and mechanical power by means of the expansion and contraction of gases and vapours.