A detrital zircon U–Pb laser ablation–inductively coupled plasma–quadrupole mass spectrometry (LA-ICP-QMS) provenance study was undertaken on samples selected from the Lower Gondwana successions preserved in the fault-bounded Bokaro and Jharia basins in India to investigate the provenance of the sediment and determine whether the strata were deposited in isolated syn-depositional graben basins or formed part of a wider regional depositional system. A total of 730 concordant U–Pb detrital zircon ages revealed six distinct age fractions: (i) a latest Neoproterozoic to earliest Cambrian age fraction (530 to 510 Ma), which tails down in some samples to older Neoproterozoic ages (650 to 630 Ma); (ii) a major age fraction with an age peak of earliest Neoproterozoic (950 Ma), accompanied in some samples by a twin Mesoproterozoic peak (1000 Ma); (iii) a middle Mesoproterozoic age fraction (1330 to 1300 Ma); (iv) a prominent earliest Mesoproterozoic zircon age fraction (1600 Ma); (v) a less well-defined late Palaeoproterozoic zircon age fraction (2100 to 1700 Ma, or 1600 Ma); and (vi) an Archaean zircon age fraction that typically comprises two zircon age fractions, namely zircons with early Neoarchaean ages (2800 to 2750 Ma) coupled with zircons with ages older than 3100 Ma. Comparison of these newly obtained age fractions with detrital zircon age data presented by Veevers & Saeed (2009) shows similarities with the Gondwana strata of the Mahanadi and Pranhita–Godavari basins, implying that strata preserved in the fault-bounded Gondwana basins in central east India formed part of a much wider regional depositional system and that they were not deposited in isolated half-graben or graben basins. Potential source regions to the Gondwana strata of the Bokaro and Jharia basins include the Eastern Ghats Mobile Belt and rock units in Antarctica.

On the 24th of June, 1885, a paper by me, entitled “Observations on some imperfectly known Madreporaria from the Cretaceous Formation of England,” was read at a meeting of the Geological Society which, encountering an adverse report from the referee, was with the consent of the Council, withdrawn by me, and published verbatim in the Geological Magazine of the same year (Dec. III, Vol. II, pp. 541–563, PI. XIV), 1885. The present communication is a continuation as well as a correction of the former one, which has become necessary from the acquisition of additional material.

Four species of Monograptus are described and the age of the strata shown to be that of the zone of M. nilssoni of the Lower Ludlow of Great Britain.

K. Aoki, B. F. Windley, S. Maruyama & S. Omori reply: First, we thank Viete, Oliver & Wilde for their interesting and thought-provoking comments on the timing of the high-pressure granulite facies (HGR) metamorphism recorded in metamorphic rocks at Cairn Leuchan, Scotland, published by Aoki et al. (2013). Based on new metamorphic data of garnetites and garnet-amphibolites at Cairn Leuchan and new zircon U–Pb ages of amphibolitized eclogite at Tomatin, we suggested in our publication that the HGR metamorphism was retrograde after eclogite facies before the c. 470 Ma ‘Barrovian metamorphism’. Viete, Oliver & Wilde however speculate that the HGR metamorphism at Cairn Leuchan may have occurred at c. 1000 Ma, as a result of their new U–Pb zircon age of the Cowhythe Gneiss at Portsoy and from previous studies of the geological structure and geochronology. We are grateful for this opportunity to describe, albeit in a preliminary manner, our new understanding and tectonic model of the Caledonian orogen in Scotland and western Ireland of which the Barrovian metamorphism is a key component. A reply to a comment is not the correct place to propose an entirely new paradigm for such a classic orogen, but we will present our model more fully in a future publication.

“Shells having the general form, of Productus, but uniformly with a narrow area on each valve, a foramen or callosity on the ventral area, small teeth, and more or less distinct teeth-sockets. The reniform vascular impression, rising from between the anterior and posterior occlusor muscular impressions, curves gently outwards, and, following a curvature somewhat parallel with the margin of the shell to below the middle of its length, is abruptly re-curved, and the extremity, turned a little backwards, terminates about halfway between the margin and the anterior extremity of the mesial septum. The cardinal process, seen from the inner side, is bilobed, and from the exterior side each of these divisions is usually bilobed.

The effect of waves on a shore depends largely on the angle of approach, for the energy of the advancing waves tends to erode the headlands and drift the products of erosion into the bays. Wave refraction applies to waves approaching the shore in any direction, but is only ideally developed in ordinary weather conditions or by approaching waves caused by distant storms. Locally developed storm waves usually approach the shore at an oblique angle to its general trend, owing to the failure of wave refraction and are the most effective where locally they meet the shore at right angles. Beach drifting will be in operation along the section of the shore which happens to be at an angle oblique to the direction of the approaching waves.

A study in the deformational patterns of oolites from the Krol Series of the Simla Himalayas has been made in the type area. The deformation in the oolites is the result of the tectonic phenomenon coupled with folding movements during the Himalayan orogeny. The deformation varies with the amount and type of the matrix surrounding the oolites. The angle between the long axis of the ellipse and the principal tectonic extension is smallest in the axial regions of the folds.

A few species of Lamellibranchs were recorded by Messrs. Marr and Koberts from the Trinucleus seticornis Beds of Haverfordwest; and though some new species may now be added to their number with the aid of the numerous specimens collected by Mr. V. M. Turnbull, yet a complete list of the species is at present impossible owing partly to the imperfect condition of many of the fossils and partly to the unsatisfactory state of our knowledge of this class as developed in British Ordovician rocks.

The lower strata of the Silurian system are, as yet, but little known. The labours of Welsh and other geologists have brought to light the large fauna of the Lingula flags; but while the Upper Cambrian has thus been established and elucidated, the beds which lie immediately above it, namely the “Arenig group,” and the Llandeilo flags, remain to be searched, and a great part of the respective fauna of each to be described.

The Areing, or Skiddaw, group of Sedwick forms the base of the true Silurian rocks; it immediately underlies the Llandeilo flags, from which it is totally distinct, although caused with them in Murchison's “Siluria.”

In the first part of this paper an account has been given of the heavy minerals of the northern part of the Leinster Granite and of the contiguous rocks in the Ballycorus district.

The subject of ‘pleochroic halos’ has become endowed with peculiar interest since Professor Joly suggested that they are due to the radio-activity of the inclusions round which they occur. On looking into such petrographical literature as I possess, it appears that very few precise observations have been made regarding these halos, and it has occurred to me, therefore, that some of my own notes on the subject may be of general interest.

Previous to 1858, the Northumberland and Durham Coalfield was considered to be destitute of any fauna other than the usual non-marine type. In 1858, J. W. Kirkby gave the first indication of marine fossils in this coalfield. He obtained specimens of Lingula credneri (Geinitz) from shales some 17 feet above the Five-Quarter seam during the sinking of a shaft at Ryhope, 3 miles south of Sunderland (9). Some of these specimens are figured by T. Davidson (2).