“Strobilocystites? kearsargensis Stauffer,” a supposed rhombiferan cystoid from the Kennett Formation, Kearsarge, California, is a diploporite cystoid tentatively assigned to Revalocystis Jaekel. This extends the stratigraphic range of the Dactylocystidae into the Silurian and is the first reported occurrence of Dactylocystidae from North America. An unusual specimen of Glansicystis baccata (Forbes) with IL1 represented by two small pentagonal plates is described. Glansicystis had four short ambulacra: I and IV have only one brachiole; II and V may have one to three brachioles.

An isolated echinoderm plate with structures which may represent pectinirhombs is described from the Whipple Cave Formation, Near Lund, Nevada. The structures differ from typical pectinirhombs and are older (Uppermost Cambrian or Basal Ordovician) than any previously described pectinirhombs.

The reverse aspect of a proximal end of I. manubriatus is described and its relation to the mode of development of some early biserial forms is briefly discussed. Two new names descriptive of types of development are proposed.

In the region east of the south-western belt of Ceylon, garnet is stable in biotite-bearing pelitic rocks which belong to the hornblende-granulite subfacies. In the south-western belt, which includes Zone B of the eastern part of the Gampaha sheet, garnet is unstable in biotite-bearing pelitic rocks, garnet reacting with biotite to produce cordierite which has a widespread occurrence in the belt to which it is confined. To accommodate the stable cordierite-bearing pelitic assemblages the erection of a cordierite-granulite subfacies is necessary. Wollastonite-bearing rocks, which commonly occur in the belt and are confined to it, belong to the cordierite-granulite subfacies.

Current-produced sole markings are not uncommon in the Pleistocene continental till deposits of Alberta, Canada. Groove, striation and prod moulds have all been recognized, characteristically occurring in close association on the undersurface of the till beds. These sedimentary structures provide a rapid means by which local ice-flow directions may be determined.

The Spitsbergen archipelago is situated in the north-westernmost part of the Barents Shelf. The structural position of the archipelago and the variety of its geological complexes make this region very important for understanding the tectonic history of the Atlantic sector of the Arctic.

Study of casts of Stegomosuchus, a small reptile from the Upper Trias of the Connecticut Valley, hitherto regarded as a pseudosuchian thecodont, suggests that the skull of Protosuchus includes two pairs of supraorbital bones, and as a consequence the narrow interorbital region indicates a closer relationship to the South African genus Notochampsa than has previously been thought. These three genera of late Triassic crocodilians are placed in the family Stegomosuchidae von Huene, 1922. Proterochampsa, from the Ischigualasto Formation of Argentina, described by Reig (1959) and Sill (1967) as an ancestral crocodile, is considered to be an extremely primitive phytosaur.

The study of echinoids and their associated limestones in the Upper Estuarine Series of Blisworth has shown that the echinoid tests have been preserved in two ways. (1) Without spines, jaw apparatus or apical disc. When whole, such tests are usually full of sediment. Echinoids of this type are usually associated with clean well-sorted fragmental limestones. (2) Bearing spines and with apical disc and jaw apparatus in place. When whole, the tests are usually full of clear crystalline calcite. Echinoids of this type are usually associated with poorly sorted, complex, muddy limestones with a high proportion of terrigenous material. The sedimentary environment and the relative rate at which the echinoid material passed through the depositional interface appears to have controlled both the limestone lithology and the condition of the echinoid material.

The beginning of melting of mineral assemblages of alkali feldspar, plagioclase and quartz in the system Ab-Or-Q-An cannot be treated in terms of eutectic points in subsystems which are defined on the basis of the ratio Ab/ An. Such subsystems do not exhibit unique melting temperatures or unique compositions of the first liquid produced. It is shown theoretically and demonstrated experimentally that these three minerals may coexist with liquid over a considerable portion of the melting range.

Lower Tertiary rocks of the Panjab Himalayas are classified under the Lower Tertiary System which comprises the Subathu Series (Upper Palaeocene-Eocene), the Dagshai Series (Upper Eocene-Lower Oligocene) and the Kasauli Series (Upper Oligocene-Lower Miocene). There is perfect stratigraphic harmony between the Subathus and the Dagshais, and the latter, in turn, grade into the Kasauli Series.

Correlation of the Lower Tertiary rocks of India, Pakistan and Burma and their European and North American equivalents is tabulated.

A flora found in a clay lens in the Corton Beds at Lowestoft indicates a late- or full-glacial type of environment during an interval in the deposition of the Corton Beds. The interval may be related to drainage changes associated with the retreat of the North Sea Drift ice and advance of the Lowestoft Till ice.

The Chalk of England contains three main Hexactinellid faunas, of Lower Cenomanian, Middle and Upper Turonian, and Lower Senonian to Maestrichtian age respectively. The third is also represented in Ireland. A number of minor faunal changes can also be recognized. The three main faunas have little in common, and their relationship is not evolutionary; the changes appear to be due to migrations. By analogy with modern forms, this is likely to reflect changes in the pattern of current circulation in the Upper Cretaceous ocean.

Outcrops of Carboniferous Limestone were examined along the coast of North Wales around Penmon in Anglesey, and Great Orme's Head, Gloddaeth and Llanddulas in Caernarvonshire and Denbighshire.

Tectonic forces have folded, jointed and faulted the Limestone, but each area has reacted differently. The differences are discussed and the effects on the different limestone units illustrated.

Caledonian structures adjacent to the areas are briefly discussed. Variation in fold strike from north to east or south-east in the Carboniferous rocks is a reflection of the change in strike in the Lower Palaeozoic rocks, as is the northwest to north strike of the faults.

It is postulated that folding and faulting of the Carboniferous Limestone areas during the Hercynian orogeny was totally guided by Pre-Cambrian and Caledonian structural trends in Anglesey and on the mainland coast, and that the southern compression during the orogeny only accentuated pre-existing trends.

A radiometric age determination on wood in tin-bearing alluvium from Selangor gives a result of about 36,000 years B.P. This is consistent with the view that the deposits formed during a period of rejuvenation of river systems during the Pleistocene. Meagre palynological evidence indicates the deposit is late Pliocene or younger.

Based on the distribution of several stratigraphically important species three distinct larger foraminiferal zones are recognized in the Middle-Upper Eocene succession of Garo Hills, Assam, India. A comparison of these zones with larger foraminiferal assemblages from other Middle-Upper Eocene successions in the Indian region is attempted and observations are made on the demarcation of the Middle and Upper Eocene boundary and the classification of the Upper Eocene succession in this region.

Twelve stages in the crystallization of the teschenite are defined by the commencement or cessation of crystallization of particular minerals. Ocellar structures, outlined by tangentially arranged biotite flakes, developed in liquid pockets after the sill had begun to consolidate, due to the coalescence of crystalline masses. It is thought that these ocellar structures were formed by the growth of gas bubbles and that this caused the expansion and fracturing of the partially consolidated sill. It is argued that the separation of the gas phase was the result of a retrograde increase in the vapour pressure during crystallization.

Drift pumice collected in December, 1964, from the Herald Cays in the western Coral Sea is chemically and petrographically a dacite, unusually low in K2O and with very calcic plagioclase. It is apparently identical to pumice washed ashore in Fiji in March, 1965; both collections are divisible into light and dark varieties on megascopic, optical and chemical criteria. This pumice is distinguishable from the widely distributed pumice of the 1962 South Sandwich eruption; it is considered to have originated along the Tonga-Kermadec ridge on the basis of available seismic and compositional data.

Tholeiitic contact rocks and a wide zone (White Allivalite) rich in primary precipitate calcic plagioclase are marginal to a layered allivalite series in a funnel-shaped intrusion. The high structural level apparently precludes the possibility that the ultrabasic layered rocks are the basal part of an accumulate from a tholeiitic magma. It is suggested, therefore, that a suspension of calcic plagioclase in a liquid more basic than basalt gave rise to an approximately equal volume of layered ultrabasic rocks by fractional crystallization. Emplacement was probably initiated as a tholeiitic cone-sheet complex, followed by the injection of the ultrabasic suspension in a volume sufficiently large to form a funnel-shaped body within the cone-sheet complex.

Various views have been expressed about the origin of the Red Sea Depression. Many earth scientists favour large-scale crustal separation and rotation of Arabia with respect to Africa—the paar theory; whereas a minority believe in a simple tensional origin. In the writer's view the almost “timeless” models presented by Drake & Girdler (1964) and Laughton (1966) are unacceptable because little of the available stratigraphic, structural and geo-morphological data was utilized in their construction. A tension system may have existed in the Red Sea area in late Pre-Cambrian and early Palaeozoic times. A depression existed in the northern part of the region in Carboniferous times and during Cretaceous times a tongue of Tethys occupied the northern and central portions of the depression. In Miocene times an extensive evaporite basin developed occupying most of the depression. The sill was situated in the Gulf of Suez Ayun Musa area.

The main and central troughs developed as a result of tension in Pliocene and later times. The Gulf of Aqaba Depression was formed by a fault system continuous with Dead Sea System which originated in (?) early Cretaceous times. The northern and central parts of the gulf were invaded by the sea in Pleistocene times.

The escarpments which bound the Red Sea Depression are in very few places fault or fault line scarps. Primarily they appear to be erosional features developed by pediplanation across the downwarped margins of the depression. In places, the shoulders and flanks were faulted later. In this way the uncon-formable nature of the contact, between the Mesozoic-Tertiary sediments and the Basement Complex (mainly Pre-Cambrian) which occurs at the foot of the escarpments, is best explained.

An electron microscope examination of beach and glacial pebbles suggests that these two environments do not impress distinctively different textures on pebble surfaces. A detailed study of surface textures of beach pebbles indicates that size reduction is predominantly an abrasional rather than solutional process. The three textural features noted, flat planar surfaces, pits and arc-shaped fractures, were characterized by an abundance of mechanical breakage blocks slightly modified by solution. All three textural types were experimentally duplicated.

The usage and synonymity of the names of some olivine-bearing feldspathoidal extrusive rocks is discussed. In the nephelinic rocks it is suggested that the terms nepheline-basalt and olivine-nemafite be abandoned, and that the use of olivine-nephelinite be continued. A similar recommendation is made for other feldspathoidal rocks.