The fertile highlands of Kenya, of which the great mountain of that name is the northern outpost, are divided from those of Abyssinia by a great desert nearly 400 miles wide. This tract is a gneiss peneplain of great age, whose degradation, without any regional interruption, has continued since Palaeozoic times. At the present date its undulations are scarcely noticeable, and its ill-supplied rivers do not often reach the coast. Such is the Uaso Nyero, which, rising from the north-western slopes of Mount Kenya, and running spasmodically for 200 miles eastwards through this desert, finally dies away in the great swamp called Lorian, which shifts its position up or down the valley in accordance with the seasons. The Tana River reaches the sea, and its valley also has the appearance of great antiquity; the long slopes down to the valley from its sides are hardly perceptible, and for two-thirds of its 400 mile course the river meanders sluggishly from one side of its valley to the other.

IN the January number of this Magazine there appeared a rejoinder by Messrs. Kitchin and Pringle to observations published by myself on their reading of the stratigraphical position of the Hunstanton Red Rock and its relation to the beds above and below. Since the following is intended as an answer to this, it is almost inevitable that it should be written in the first person. For this unavoidable egotism apologies are offered to readers.

Specimens I, 1–8 were studied. Probably those measured under Dr. Reed's heads I and II refer to 1 and 3 respectively. Specimen I is hereby selected as Holotype.

This paper gives the results of investigations made during the early part of the present year with the object of elucidating the relation of the Coal-measures to the Lower Carboniferous rocks in the Clapton and Clevedon districts of Somersetshire.

Dr. Mantell, in his classical work, the “Fossils of the South Downs,” figured two large compressed and lanciform teeth preserved in his collection and obtained from the Chalk at Lewes, as respectively the teeth, of an unknown fish and of a species of Squalus. Similar teeth, and from the same collection, were subsequently figured and described by Prof. Louis Agassiz, who, from external characters chiefly, considered them to have belonged to a Sphyrænoid fish, and he referred them to an American species founded by Dr. Harlan upon portions of jaws with teeth in situ found in a Cretaceous deposit in the State of New Jersey, but described by him as remains of a Saurian, and to which he gave the name of Saurocephalus lanciformis. At the time when Agassiz referred these teeth to Harlan's species, and determined their ichthyic character, he had not seen the American fossils; but he states that these conclusions were subsequently confirmed by Prof. Owen's description and drawings of the microscopic structure, and of teeth of the natural size of the Saurocephalus lanciformis, Harl., in his “Odontography,” p. 130, pl. 55. But Prof. Owen's researches were made upon a genuine tooth of the American fossil sent to him by Dr. Harlan, and not upon an English specimen.

‘Lower Old Red Sandstone’ deposits preserved by cauldron subsidence at Glen Coe, Scotland have hitherto lacked secure biostratigraphical age constraint. A sporomorph assemblage recovered from basal sediments of these deposits permits age determination, despite being highly carbonized. The sporomorph assemblage is correlated with the micrornatus-newportensis Sporomorph Assemblage Biozone, indicating a late early-early late Lochkovian age (early Devonian). Sporomorph assemblages from basal sediments of the ‘Lower Old Red Sandstone’ sequence at nearby Lorne, a suggested correlative of the Glen Coe deposits, are older (latest Pridoli-earliest Lochkovian age). However, the new biostratigraphical data do not preclude the possibility that the Glen Coe and Lorne deposits are lithological correlatives and the basal sediments are diachronous.

A new fossiliferous section in the Coralline Crag of Suffolk is described, and its fauna is analysed as a clue to the conditions under which these beds were formed; in particular, the theory that the temperature of the Crag sea was affected by the alternate breaching and closing of land-bridges to the north and south of the North Sea area is considered unnecessary to account for the facts as seen in the field. Further, the Coralline Crag is correlated with the Astian formation of the Mediterranean, and reasons are brought forward to show that the supposed “Boytonian” Zone of the Coralline Crag does in fact not exist.

The mafic and felsic Haertaolegai intrusions crop out in Urad Zhongqi, western Inner Mongolia and are dominated by monzogranite, porphyritic granite, and gabbroic diorite intrusions. We investigate the tectonic setting, geochronology, and anorogenic characteristics of the western Inner Mongolia through field investigation, microscopic and geochemical analyses of samples from the Haertaolegai bimodal intrusions and laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) zircon U–Pb dating of gabbroic diorite and adakitic granites. Petrographic and geochemical studies of the bimodal intrusions indicate that the gabbroic diorites formed from a primary magma generated by the partial melting of lithospheric mantle material that had previously been modified by subduction-related fluids. The felsic rocks are high-K calc-alkaline and metaluminous, have characteristics of adakitic rocks and were generated during the partial melting of juvenile crustal material. Zircon U–Pb dating indicates that the felsic portion of this pluton was emplaced during late Carboniferous – early Permian time, with the mafic portion of the pluton emplaced during early Permian time. The zircons of adamellites have ɛHf(t) values and TDM2 ages of +1.0 to +2.7 and 1032–1128 Ma, respectively, suggesting that they formed from magmas generated by partial melting of juvenile Mesoproterozoic lower crust. These data, combined with the geology of the region, indicate that the late Carboniferous – early Permian bimodal intrusive rocks in western Inner Mongolia record a transitional period from collisional compression to post-collisional extension. These results indicate that the Paleo-Asian Ocean in western Inner Mongolia closed before 300 Ma.

Since the publication of the paper by the present author in 1905 on the Classification of the Phacopidae, a considerable advance has been made in our knowledge of this family as a result of further and better material being obtained, and of new discoveries in different parts of the world. Many new genera and subgenera have been instituted, and modifications or limitations of some of the old terms have been introduced by various authors. The work of Wedekind, Clarke, Rud. and E. Richter, and Kozlowski has specially dealt with questions of classification, but there is still a considerable amount of diversity in the usage and application of the generic and subgeneric names.

The first American mammal found in the Jurassic, and a large proportion of those since discovered, belong to a peculiar family which the writer has called the Dryolestidœ. It includes several genera and numerous species from America, and is likewise represented among the forms found in Europe.

Whilst studying the sedimentary roofing-slates of North Wales and Cornwall, and allied materials, my attention was also directed to those most interesting rocks, the ash-slates of the Lake District, often externally so closely resembling some of the Welsh and Cornish examples, though differing so much in origin. In course of time I have collected, and had sections prepared from, a considerable number of specimens from many quarries and other places at various parts of the district, both very fine-grained wellcleaved actual roofing-slates and also the attendant coarser beds.

In this country the best known species of Tetradella is T. complicata (Salter), a form which is usually regarded as typical of Caradoc rocks and has been widely quoted in faunal lists as such. It happens, however, that this species was originally described as Beyrichia complicata, by Salter (Phillips and Salter, 1848, p. 352, pi. 8, fig. 16) from the Llandeilo Beds of Llan Mill, near Narberth, and it is extremely unlikely that it ever occurs in Caradoc beds. This confusion has no doubt arisen from the inaccuracies in Salter's original figure, the briefness of the accompanying description and the fact that McCoy figured what is obviously another species of Tetradella under the same name from the Caradoc Beds of Pont y Meibion (McCoy, 1851, pl. IE, fig. 3). At a later date T. R. Jones refigured T. complicata from Llan Mill with more accuracy than Salter and with a fuller description, but unfortunately figured under the same name a form from the Caradoc of Harnage, giving also a list of Llandeilo and Bala localities where T. complicata was supposed to occur (Jones, T. R., 1855, pp. 163–5, pl. vi, figs. 1–5). In addition to this figures have appeared in various textbooks and similar works of a general nature which are usually too poor for specific determination although it is obvious that in the main they cannot be referred to Tetradella complicata (Salter).

Searle (2022) argues, based on data from Scotland alone, that the deformation and metamorphism of the Scottish Highlands is continuously diachronous from the early Ordovician (Grampian) in the Dalradian of the Grampian Highlands to the mid-Silurian (Scandian) in the Moine of the Northwest Highlands. Necessarily, he disputes substantial offset along the Great Glen Fault (GGF). He compares the Scottish Caledonides with the Himalayas. We take the different view, which also considers evidence from along-strike in Ireland and Newfoundland, that the Grampian and Scandian orogenies were discrete events. The Grampian Orogeny involved major deformation and metamorphism across the Grampian and Northwest Highlands to the Moine Thrust Zone, whereas the Scandian Orogeny affected only the Northwest Highlands. The early Ordovician Grampian Orogeny was generated by the collision and obduction of an oceanic arc-ophiolite with and onto the Laurentian continent. The mid-Silurian Scandian Orogeny was caused by continental collision between Laurentia and Baltica. Late Silurian – early Devonian sinistral slip along the GGF emplaced the the Moine of the Northwest Highlands from a distant location to the north in the Scandian collision zone, against the Dalradian, which had not been involved in the Scandian collision. We outline several (eight) arguments that we believe contradict evidence for progressive northwestward propagation of a Himalaya-style thrust wedge from the early Ordovician to the mid-Silurian.

In studying the evolution and distribution of the Proboscidea and the arrival of man in Great Britain (Osborn, 1922, 1922a, 1922b), the writer has recently had occasion to review the faunal researches of Lydekker and Newton, and the collection of Mr. A. C. Savin, in connexion with the very interesting question of the geologic correlation of Great Britain with the Upper Pliocene fauna of Europeto the south-east, and of the Scandinavian Glaciation I on the north, with the advent of the northern forest, the boreal, and the Arctic mammal fauna of Great Britain.

Structural analysis, petrochronology and metamorphic petrology enable identification and bracketing of the timing of a newly mapped high-temperature ductile shear zone (Jagat Shear Zone (JSZ)) in the Himalayan metamorphic core in Central-Western Nepal. In situ U-Th-Pb monazite petrochronology constrains the timing of top-to-the-S/SW shearing between 28–27 Ma and 17 Ma. Burial and prograde metamorphisms in footwall rocks were linked to thrust-sense movement along the JSZ, while the hanging wall rocks were retrogressed and exhumed. The identification and age of the JSZ (as part of a regional system of shear zones: the High Himalayan Discontinuity (HHD)) coupled with the localization and timing of activity of the Main Central Thrust (MCT) (i) fills a gap in tracing the HHD along orogenic strike, (ii) supports the identification of the position and timing of the long-debated MCT and (iii) helps to place the boundaries of the Himalayan metamorphic core and its internal architecture. Thus, our study is a significant step towards a precise identification of the burial, assembly and exhumation mechanisms of the Himalayan metamorphic core.

A new Ordovician stromatoporoid species, Labechia aldonensis, is described and illustrated from the Stinchar Limestone (Barr Group) of the Girvan District, Scotland.

A number of coarse-grained blocks, consisting of forsteritic olivine, chrome-diopside, calcic plagioclase, and chromite in varying proportions, were found in an ankaramitic basalt on Faial. With one exception, the blocks show remarkably little alteration. There is no evidence of zoning in any of the minerals. Indications of strain are frequent. Dark scoriaceous material is often present along intercrystal boundaries and fractures. The textures and gradations in composition suggest that these blocks were formed by crystal accumulation.

The cardinal process in the Productidae is divided into two main types, either bi- or trilobed. The process in several species, illustrating each type, is described and figured, and the development of both types compared.