The Tso Morari Crystalline complex (TMCC) of eastern Ladakh, India, is part of the north Indian continental margin and is characterized by eclogitic enclaves embedded within ortho- and paragneisses known as the Puga Gneiss. Two fault zones bound the TMCC: the Karzok fault to the southwest and the Zildat fault to the northeast. In the present study, we carried out Electron Backscatter Diffraction study of quartz of 10 samples collected from the Puga Gneiss. The relict and recrystallized quartz grains were treated separately to understand the deformation conditions of the Puga Gneiss during early and late deformation stages related to UHP metamorphism and final stage of exhumation during retrogression, respectively. Microstructural observations suggest dynamic recrystallization in quartz and plagioclase at different temperature ranges. Misorientation analysis of both relict and recrystallized quartz grains reveals presence of Dauphiné Twins. Lattice preferred Orientation (LPO) of <c> axis of relict quartz grains generally shows more than one point maxima indicating that the relict grains preserve LPO developed during different stages of metamorphism/deformation. On the other hand, LPO of <c> axis of recrystallized grains from Karzok and Zildat fault zones shows asymmetric single girdle either normal or at an angle to the foliation plane, which suggests simple shear. We conclude that grain size reduction and recrystallization of the Puga Gneiss was greatly influenced by Dauphiné Twin and the final exhumation of the TMCC took place in a simple shear environment aided by activity along its two binding fault zones.

Before proceeding further with these notes on the geology of The Lizard it will make matters clearer if the sequence of rocks is given as established by the Cornish and other geologists, but I have ventured to introduce modifications which will be explained later:—

Youngest: Kennack granite.

Kennack gneisses, consisting of doleritic and granitic components.

Portable apparatus for obtaining small oriented cores for geophysical or geological purposes is described. It consists of a 34 c.c. two-stroke engine with a 12 ft. long flexible shaft to a drilling head which accommodates the drilling bit and includes a pipe through which coolant from a pressure container may pass. All this weighs under 50 lb. Imperfectly cylindrical specimens may be obtained by hand drilling, or perfect cores with the aid of either of the two rigs described. The first weighs 21 lb. and allows a number of closely spaced specimens from horizontal and inclined outcrops to be obtained. The second weighs 15 lb. and is for obtaining specimens some fixed distance apart from more difficult vertical faces. Magnetic and non-magnetic orienting devices are described. The merits of the method of sampling are briefly discussed.

The Unconformity between the Green and Skiddaw Slates, which I pointed out in the last number of the Geological Magazine, (see p. 56) as exhibited between Grange in Borrowdale and Dale Head will, I think, explain satisfactorily the Geology of Derwentwater

Summary. Mechanisms forming silicic segregations from basaltic magmas are considered of primary importance when dealing with magmatic problems. However, the processes which give rise to silicic segregations from basaltic magmas are so far obscure. Fortunately, the discovery of spheroidal felsic masses in some basic rocks of Western Sicily throws light on this subject. To clarify the relationships between felsic and basic fractions particular attention has been paid to the interactions which occurred at their contact. Textural evidence indicates that the accretion mechanism of the Sicilian felsic segregations tends to obliterate the silicate liquid immiscibility effects and suggests that the formation of silicic segregations is a consequence of liquid unmixing phenomena.

It has long been known that garnet and other heavy minerals occur in many of the sedimentary beds of the North of England. Among such, where visual proof is easy, are the Inghoe Grits, particularly at Shaftoe, and the Dunstanburgh sandstone at Cullernose Point. Hutchings examined washings of the shales at Seaton Sluice and found zircons in large numbers, along with angular colourless garnet, rutile, anatase, tourmaline, sphene and barytes. In a later study by the same author of the sedimentary beds metamorphosed by the Whin Sill, it was shown that small garnets are very plentiful, especially in the calcareous shales, and are accompanied by augite, hornblende, epidote, sphene, idocrase, wollastonite and other minerals. Kellett made an extended investigation of the heavy minerals in the Coal Measures of County Durham and found 0·4 per cent of these in the sandstone under the Hutton seam (this is the only datum of Kellett's strictly comparable with our results). Zircon proved to be the commonest mineral in these beds; next in order came rutile and tourmaline, while garnet was quite subsidiary.

The superficial deposits of the Co. of Wexford, containing a rich marine fauna, have been referred to in Professor E. Forbes's Memoir on “The Geological Relations of the existing Fauna and Flora of the British Isles.”

The weathered surfaces of the limestones and calcareous shales of the Lower Lias in Somerset and Dorset sometimes exhibit curious paired markings. On careful examination these prove to be cross sections of U-shaped burrows of organic origin, appearing as two circular markings connected by a shallow depression or by a slight variation in the character of the matrix. Similar burrows have been described from the Lower Estuarine sandstone of Blea Wyke, on the Yorkshire coast. Dr. F. A. Bather has discussed their origin and structure in detail and has assigned them to the genus Arenicolites, which was established by J. W. Salter for “all worm burrows with double openings”. Other species of the genus have been described from arenaceous and argillaceous beds of Longmyndian, Ordovician, and Upper Carboniferous age, but as far as the author is aware, the species here recorded is the first that has been mentioned from the calcareous rocks of the Lower Lias of England.

One of D'Orbigny's subsidiary methods of classification was to create separate genera for those species which heap layer upon layer of zoœcia by prefixing ‘Mult’ or ‘Multi’ to the name of the genus to which they would but for this habit of growth be referred. It is rather surprising that he did not have occasion to create a genus Multeschara, as there are two species in the English Chalk which he could only have dealt with in this way. They are of interest in their bearing on the question of the admissibility of methods of growth in classifying the Cheilostomata, as they are linked together by a most adventitious peculiarity in growth and one which does not involve any zoœcial modification. They offer therefore a case in which, if those who will not allow to zoarial growth and measure of classificatory value are right, it might be anticipated that species so linked together would be a heterogeneous assembly and not even consistent in this habit of growth. Such an anticipation would hardly be borne out in the case of the English Chalk. The Multescharine habit is practically confined to the two following species, which are most distinctly homogeneous, and neither of which, as far as my experience goes, ever adopts any other mode of growth (except for occasional specimens of Rhagasostoma palpigerum of purely Escharine habit, which may fairly be regarded as cut off prematurely in the Escharine stage, through which every ‘Multeschara’ must pass).

The existence of rocks possessing, when the laminæ are not too thick, the property of flexibility has long been known. Upon flexible sandstone (“Itacolumite”) a great deal has been written at different times, and of late years important work has been done which renders it necessary to greatly modify the opinions formerly held with regard to this rock. Notwithstanding the interest which, is attached to the subject, it is one very much neglected by our textbooks, the British, either ignoring it altogether, or treating it with the utmost brevity, the German, while sometimes referring to it at considerable length, do not do more than enunciate the old views. To Prof. Judd—who has kindly aided me with advice, and by affording facilities for preparing this paper—I owe the suggestion that it would therefore be useful to give a résumé of the present state of our knowledge upon the flexibility of rocks in general.

Although unwilling to admit that in the history of our Earth special and peculiar conditions have prevailed at any period since the first advent of organic beings, yet we cannot doubt, that during particular eras, circumstances favoured the development of special groups of organisms which, in consequence, flourished in greater perfection and numbers than the rest.

New exposures of Upper Llandovery and Cambrian strata are described from the southern Malvern Hills. The rocks occur in a small faulted outlier between Midsummer and Hollybush Hills, within the main Pre-Cambrian outcrop. The Cambrian is represented by a thin succession of Malvern Quartzite and Hollybush Sandstone and is overlain by an Upper Llandovery limestone with a basal conglomerate containing rounded pebbles of Hollybush Sandstone. The new exposures weaken the case for a major post-Llandoverian fault at the western boundary of the local Pre-Cambrian outcrop, but provide further evidence of an important phase of pre-Llandoverian tectonism in the Malvern area.

Faunas of brachiopods, graptolites and conodonts from the Llandoverian limestone allow a correlation with the C5 substage of the shelly sequence, the griestoniensis graptolite zone and a position near the boundary of the celloni and amorphognathoides conodont zones.

Microscope studies of a flattened fold are consistent with conclusions from macroscopic observations that whereas mudstone cleavage development may have resulted from a laminar-type flow governed by competent confining sandstone beds, the sandstone cleavage appears to be related to the dilation of texture during the early stages of deformation. Continued deformation results in a textural disruption of the initially competent sandstone, which is considered to allow flattening.

It must be admitted that first impressions are to a certain extent instinctive, and need not, therefore, be taken for more than they are worth. To do any really valuable work in such a troubled district as Assynt would require a considerable length of time. Still, after having been nearly a fortnight in the place—a fortnight in which the rainy days and the dry ones were about equally balanced —it is almost impossible to avoid forming some idea as to the respective merits of the interpretations which have been put forth. And this one is all the more apt to do in order to be able to institute comparisons with other districts of the North-West already visited in previous years.