Viscosities of liquid albite (NaAlSi3O8) and a Himalayan leucogranite were measured near the glass transition at a pressure of one atmosphere for water contents of 0, 2·8 and 3·4 wt.%. Measured viscosities range from 1013·8 Pa. s at 935 K to 109·0 Pa. s at 1119 K for anhydrous granite, and from 1010·2 Pa. s at 760 K to 1012·9 Pa. s at 658 K for granite containing 3·4 wt.% H2O. The leucogranite is the first naturally occurring liquid composition to be investigated over the wide range of T-X(H2O) conditions which may be encountered in both plutonic and volcanic settings. At typical magmatic temperatures of 750°C, the viscosity of the leucogranite is 1011·0 Pa. s for the anhydrous liquid, dropping to 106·5 Pa. s for a water content of 3 wt.% H2O. For the same temperature, the viscosity of liquid NaAlSi3O8 is reduced from 1012·2 to 106·3 Pa. s by the addition of 1·9 wt.% H2O. Combined with published high-temperature viscosity data, these results confirm that water reduces the viscosity of NaAlSi3O8 liquids to a much greater degree than that of natural leucogranitic liquids. Furthermore, the viscosity of NaAlSi3O8 liquid becomes substantially nonArrhenian at water contents as low as 1 wt.% H2O, while that of the leucogranite appears to remain close to Arrhenian to at least 3 wt.% H2O, and viscosity–temperature relationships for hydrous leucogranites must be nearly Arrhenian over a wide range of temperature and viscosity. Therefore, the viscosity of hydrous NaAlSi3O8 liquid does not provide a good model for natural granitic or rhyolitic liquids, especially at lower temperatures and water contents.

Qualitatively, the differences can be explained in terms of configurational entropy theory because the addition of water should lead to higher entropies of mixing in simple model compositions than in complex natural compositions. This hypothesis also explains why the water reduces magma viscosity to a larger degree at low temperatures, and is consistent with published viscosity data for hydrous liquid compositions ranging from NaAlSi3O8 and synthetic haplogranites to natural samples. Therefore, predictive models of magma viscosity need to account for compositional variations in more detail than via simple approximations of the degree of polymerisation of the melt structure.

Three new genera and seventeen new species of trilobites from the Flags with Valcourea confinis (Salter) of the Girvan District are described and named, and thirty-six species are figured. The genera constitute a normal Middle Ordovician assemblage for the Girvan District; none of the species is known elsewhere. There is a close resemblance to the fauna of the Lower Edinburg Formation of the Appalachian Valley of the U.S.A., and many of the generic stocks are known earlier only from the Chazy and Lincolnshire Formations of North America.

Approximately 700 samples from five slate, three marble and five quartzite units have been analysed for 26 elements to determine the use of geochemistry in stratigraphic correlation. Statistical treatment of the data has established that for all the slates and marbles, and certain of the quartzites, geochemistry is a viable method of distinguishing units of similar lithology. The most useful elements for distinguishing the four main slate units are P, Cr. Zn, Cu and, to a lesser extent, Rb, Sr, Y, Nb, Ba, La and Ce. Sr may indicate climatic changes or variable organic activity. The three marble units were considered as three limestone and three dolostone types. Dolostones are distinguished by high insoluble residue contents and the elements that distinguish between the dolostones are heavily influenced by these. Limestones, however, have very large differences in Sr. SiO2, Al2O3, K2O, Cr, Mn, Cu, Rb, Sr, Y and Zr have been used in discrimint function analysis. These parameters are strongly controlled by the insoluble residue with Al2O3, K2O, Cr and Rb being correlated with shaley impurities and SiO2, TiO2 and Zr with sandy impurities. Sr, Pb, Y and Zn, and to a lesser extent S and Mn, appear to be associated with the carbonate fraction.

The quartzites were found to be of three major types: (1) a very variable deltaic deposit (Appin Quartzite Formation), (2) marine bodies of immature quartz sands (Glen Coe and Eilde Quartzite formations) and (3) highly mature quartz sands (Binnein Quartzite Formation and northerly outcrops of the Glen Coe Quartzite Formation). It is possible to distinguish these three types on the basis of some trace elements (Zn, Rb, Sr, Y, Ba, La, Ce) but it is not feasible to distinguish between the Glen Coe and Eilde quartzites purely on geochemistry. The Eilde Flags, an immature estuarine sandstone, has a geochemistry intermediate between that of the quartzites and the pelites, although with higher CaO, Zr and Ba than either.

Dr James Hutton was the son of Mr William Hutton, merchant in Edinburgh, and was born in that city on the 3d of June 1726. His father, a man highly respected for his good sense and integrity, and who for some years held the office of City Treasurer, died while James was very young. The care of her son's education devolved of course on Mrs Hutton, who appears to have been well qualified for discharging this double portion of parental duty. She resolved to bestow on him a liberal education, and sent him first to the High School of Edinburgh, and afterwards to the University, where he entered as a student of humanity in November, 1740.

A major transcurrent fault in the zone of the Iapetus suture in eastern Ireland separates Ordovician (pre-Ashgill) terranes. The stratigraphy of each terrane belongs to a dismembered volcanic arc system: the northern terrane is characterised by acid plinian eruptions and derivative sediments which are displaced relative to the andesitic southern terrane volcanism. Each was a separate palaeoenvironment with its own lithostratigraphical character and faunal elements which were juxtaposed across the fault. However, the late Ashgill to Silurian sediments in both terranes form part of a regional overstep sequence which links across the suture zone, such that the palaeogeographical contrasts were eliminated by the Silurian. The inference is that the detached terranes were gradually amalgamated by late Ordovician transtensional movements. This occurred when regional scale subduction-related volcanism had ended. Final assembly by early Devonian sinistral transpressive movements juxtaposed a northern terrane, akin to the Lake District/SE Ireland calcalkaline volcanic province, with a southern terrane in the tholeiitic province of eastern Ireland. As distinct from a singular fault trace, the Iapetus suture is regarded as a 100 km wide zone of anastomosing late Caledonian transcurrent faults whose precursors were active during late Ordovician (i.e. Taconic) terrane amalgamation.

The stem turtle Eileanchelys waldmani is known from the Bathonian deposits of the Kilmaluag Formation, Isle of Skye, Scotland. A description of all the currently available material, including several skulls and shells, is provided herein. Eileanchelys waldmani is characterised by a mosaic of plesiomorphic and derived features. The former include a flat vomer, a reduced posterior extension of the pterygoid, the absence of flooring of the cavum acustico-jugulare, the absence of proper recessus scalae tympani, wide vertebral scales, a vertebral 3–4 sulcus on neural 6, a pair of mesoplastra meeting medially, and platycoelous cervical vertebrae. Derived features include a prefrontal–vomer contact, an elongate postorbital skull, a well-developed antrum postoticum, and a slender processus interfenestralis of the opisthotic. Eileanchelys waldmani also possesses unique features such as a possible ninth neural or supernumerary suprapygal of unusual shape, as well as a broad first suprapygal that contacts the peripherals laterally. Additionally, E. waldmani documents the evolution of the vomer and basicranium from basalmost turtles to the crown-group.

My dear Sir,

As I see by a notice in your Journal, No. 13., which has just reached my hands, that your attention has been occupied by the phenomena of Coloured Flames, and the Absorption of Coloured Light by Diaphanous Bodies; and that you have been successful in the very valuable discovery of a manageable flame, discharging a homogeneous yellow light of an invariable character, I shall perhaps be excused, while the contents of your paper are unknown to me more particularly, for stating some phenomena Which I have myself observed, relative to this highly interesting department of physical optics.

Palynological investigations were made at two sites in south-west Scotland where peat bogs overlying late Quaternary marine clays and sands were dated by reference to the established British pollen zonation. The “25 foot” shoreline was formed during late Zone VI and early VIIa near Dumfries (c. 8100 to 6600 years B.P.), while the “50 foot” beach near Campbeltown has been referred to Zone III (ending c. 10,000 years B.P.). Close-interval analysis of the upper sections of the pollen diagrams has allowed the recognition of human interference with the vegetation. Minor short-term changes in Zone VI have been tentatively referred to Mesolithic activities, while from Neolithic times (Zone VIIb) onwards there is evidence for an increasingly effective modification of the natural environment. The pollen diagrams allow some conclusions to be drawn about the types of farming (including cereal cultivation) which were characteristic of the settlements near Dumfries and in south Kintyre.

Since we had the pleasure of working out the Mollusca obtained by the Scottish National Antarctic Expedition, Dr W. S. Bruce has kindly transmitted to our care some additional material, overlooked in the first instance, and taken (a) from deposits from jars in which Sponges were placed; (b) from Algæ and other growths, principally coming from Scotia Bay; and (c) from a new species of Cephalodiscus.

The layered syenites in the Klokken intrusion consist of horizons of fine-grained, granular-textured ferroaugite syenite showing inverted cryptic layering, interleaved with coarser, laminated, more fractionated hedenbergite syenite. Distribution of hydrous mafic phases indicates build-up of water in parallel with magmatic evolution, and druses and pegmatitic segregations in the laminated syenites are evidence for late development of a gas phase. Feldspar bulk compositions are close to the minimum on the Ab-Or binary, with An decreasing from An7 to An1 with fractionation, and normal zoning in cryptoperthite crystals. Feldspars in granular syenites are transparent coherent cryptoperthites or braid microperthites; An-content is probably the main control of fine-perthite coarseness. Laminated syenite feldspars are turbid, coarse patch microperthites with rare relics of braid textures. This non-coherent coarsening was caused by interactions between feldspars and water entrapped at magmatic temperatures which was retained within the original lithologies to low subsolidus temperatures. Fe-Ti oxides reflect this water distribution, with regular trellis ilmenite-titanomagnetite intergrowths in less fractionated rocks and ragged granule exsolution in more advanced syenites. The sharp change in exsolution textures at granular-laminated syenite boundaries implies steep water-gradients within these interleaved rock types. Water was unable to penetrate the granular layers and did not circulate freely in the cooling intrusion.

For the opportunity of examining these specimens I am indebted to Dr W. S. Bruce, the leader of the Scottish National Antarctic Expedition, 1902–1904. I should like to take this opportunity of expressing my thanks to him, and also to Dr Marett Tims for his assistance during the preparation of the paper.

Eldeceeon rolfei gen. et sp. nov. a primitive anthracosaur from the Brigantian of East Kirkton, Scotland, is described. Uniquely among non-mammalian tetrapods, its ribs are restricted to the anterior half of the presacral column. Eldeceeon lacks the diagnostic features of the two suborders of anthracosaur, the Anthracosauroideae and Seymouriamorpha, and may represent their sister group.

One main object of the present brief paper is to take advantage of the results obtained by Kirkman, and thus to extend my census of distinct forms to knottiness of the 8th and 9th orders; for the carrying out of which, by my own methods, I could not find time. But I employ the opportunity to give, in a more extended form than that in the short abstract in the Proceedings, some results connected with the general subject of knots, which were communicated to the Society on January 6, 1879, as well as others communicated at a later date, but not yet printed even in abstract.

The Clyde Plateau Lavas which are part of the Lower Carboniferous succession in the west of Scotland form the main mass of the Campsie Hills in Stirlingshire and the Kilpatrick Hills in Dunbartonshire. Below the lavas at the western end of the Campsie Hills are cement-stones and sandstones of the Ballagan Series. These are the lowest beds of the Carboniferous in this area, and in places are seen to overlie without apparent unconformity the Upper Old Red Sandstone. Few fossils have been found in them; the only plants so far recorded are Asterocalamites scrobiculatus Schloth. sp. and Alcicornopteris convoluta Kidst. (Walton, Weir and Leitch, 1938, p. 1345). All that may be said with certainty is that these beds are part of the Calciferous Sandstone Series and are probably the equivalent of the Cement-stone Group. In the Edinburgh area Alcicornopteris convoluta has been found at the base of the Cement-stone Group in beds which lie conformably on the Upper Old Red Sandstone. In the Kilpatrick Hills there are sandstones, shales and thin coal seams below the lavas in Glenarbuck and near the Loch Humphrey Burn. From the latter locality Scott (1924, p. 569) has recorded Calamopitys radiata Scott, C. zonata Kidston, Bilignea solida Kidst. and B. resinosa Scott, which were found in coarse volcanic ash.

Bohemian specimens of the phacopacean trilobites Reedops cephalotes (Hawle and Corda,) R. sternbergi (Hawle and Corda) and R. bronni (Barrande) have very well preserved schizochroal eyes. The sizes and distribution patterns of the eye lenses were studied and in R. sternbergi and R. bronni the angular bearings of all the lenses were measured, giving the visual range of the whole eye.

The internal anatomy of the eyes was also investigated, mainly from cut and polished sections. In many respects their morphology was comparable with that described previously in the Silurian and Devonian phacopaceans Phacops latifrons (Bronn) and Ananaspis communis (Barrande). The intralensar structures, however, are unlike those of P. latifrons and A. communis but bear a strong resemblance to the intralensar bowls of the Ordovician Zeliszkellinae, an early group believed to have been ancestral both to dalmanitaccan and post-Ordovician phacopacean stocks.

A brief history of the evolution of schizochroal eyes is given, some distinctive evolutionary trends are noted and the relationship of the structural pattern in Reedops is discussed with reference to that in other Phacopina.

The early developmental history of the ferret up to the present has not been made the subject of a detailed critical description. The early stages of certain other Carnivora have been described, and Professor Hill (1924) in the introduction to his paper, “The Early Development of the Cat,” gives a summary of the literature of the subject.

The only papers relating to the early development of the ferret are a short paper by Professor Robinson (1925) and four papers by Professor Mainland (1930, 1931a, 1931b, and 1932).

Two plants are described from fragmentary remains preserved in the Windyfield chert, situated c. 600 m from the classic Rhynie chert locality. Both are sometimes coated by a microbial film. The larger, fertile axes are placed in the new genus and species Ventarura lyonii. They possess a distinctive, sclerenchymatous middle cortex and terete xylem, and marginally dehiscent, lateral sporangia. The new taxon is similar to the Rhynie zosterophyll Trichopherophyton teuchansii, but is placed in a new genus on sporangial differences. Associated smaller axes with unicellular epidermal outgrowths lack the middle cortex of the larger axes and often have medullated protosteles. They are interpreted as subterranean rhizomes and probably belong to the new fertile taxon, but organic continuity between the two has not been demonstrated.

In a previous paper (4) the quantitative distribution of the molluscs and polychætes in certain intertidal muds and sands on the Scottish Coast was discussed, but there still remained several other types of shore such as (a) a river mud-flat, (b) grounds at the heads of sea lochs on the West Coast, and (c) the more exposed shores of the Western Islands, where conditions might possibly differ greatly from those already considered, with corresponding changes in the fauna. Since the publication of the first paper quantitative samples have been collected in each of these areas. Taking the survey as a whole, collections have now been made on such widely different parts of the coast that the peculiarities of the distribution of the above two groups can be stated with a fair degree of accuracy. The present paper is divided into two sections, the first dealing with the additional observations, the second with the survey as a whole.

The striking morphological similarity that exists between appendages of the extant portunid crabs, such as Callinectes sapidus, and those of the extinet eurypterids has long been noted. The fifth pair of pereiopods in blue crags and other portunids are modified to form the broad, flat, highly mobile ‘swim paddles.’ A nearly identical modification is seen in the sixth pair of prosomal appendages of many eurypterids. The similarities are due to convergence and not to shared descent.

The kinetics of blue crab swimming were studied using high speed films. The animals are capable of slow upwards locomotion (‘hovering’) and rapid sideways swimming. The blue crab paddles apparently act as reciprocating hydrofoils, employing well-understood principles of lift and thrust generation to overcome the animal's weight and drag. Experimental studies indicated that the paddles are capable of producing appreciable amounts of lift. Drag on the body and paddles was also determined. Resxults are similar to those obtained in previous studies of bird and insect flight.

The physical principles employed to study blue crab swimming can be applied to the study of eurypterid locomotion. The eurypterid paddles may have functioned as hydrofoils, producing lift and thrust on forestroke and backstroke. Eurypterids were probably highly agile and manoueverable swimmers, capable of hovering and of high speed swimming. This model predicts observed morphological correlates. Predicted morphological correlates of earlier models (often based on analogies with Limulus) were not found.

The observed convergence between eurypterids and blue crabs may have resulted from similar functional constraints and parallel phylogenetic histories.

Various types of trilobite exoskeletal sculpture are described and referred to a simple classification. Thin-section and surface examination of many such sculptural features shows them to be remnants of distinct cuticular organelles, which probably had a sensory function. The supposed sensory structures of well-preserved specimens of Phacops rana (Green) are described in detail and their presumed specific functions considered. Mapping sensilla distribution over the Phacops rana dorsal exoskeleton shows a distinctive pattern conveniently divisible into nine inferred sensory fields with the densest sensory concentrations on the head and margins of the dorsal shield.

Conclusions on the importance of these sensory fields in mediating the trilobite's behaviour are combined with evidence from general morphology, palaeocology and evolutionary trends to suggest that Phacops rana was an active benthonic animal with a dual trophic capability lending considerable flexibility in adaptive radiation.

The P. rana hypostomal suture, consisting of two short coplanar lateral branches, is described for the first time, indicating that the hypostoma had considerable freedom of movement, possibly connected with ingestion of bulky food.