We study the largest exposed example of an early Cambrian palaeokarst, associated with laterites and developed during rifting of the Ossa–Morena Zone. The lithostratigraphy, biostratigraphy, facies and the genesis reflect episodes of sea-level fall (Cerro del Hierro Regression) related to tectonic events and palaeoclimate. This palaeokarst can be primarily considered as the result of early Cambrian polyphase karstification in an extensional tectonic regime, later modified by Neogene–Quaternary geomorphological processes. The event may correlate with other regressive events of a similar age in Spain, Italy, United Kingdom, South America and Australia. This episode also has local names (e.g. Cerro del Hierro Regression in the Mediterranean region; Woodlands Regression in the UK). It is sometimes accompanied by additional karst development outside of Spain that is compared and interpreted in a global context.

The district selected for this article embraces a very unusual variety of geological phenomena, consisting of different kinds of recent gravels and Tertiary deposits, Greensand table-lands and patches, Triassic sandstone and conglomerate, rocks belonging to the interval between the Trias and uppermost Silurian strata, trap, and granite.

Sir,—The Geological Magazine for August, p. 394, contains a report of a paper communicated by the Rev. J. M. Mello to the Geological Society, on the 22nd June, 1870, on the above subject. On the 7th September, 1869, I had the honour to read a paper on the same subject to the Natural Science Section of the Nottingham Literary and Philosophical Society. Hence I beg to claim priority in publication on behalf of the above Society. Apart from this, I, of course, do not complain that Mr. Mello should happen to select a very interesting section like that in Tideswell Dale, no doubt being quite unaware that I had already published an account of the same. The sole, though rather dubious, deduction that the author is reported to have made, is “that the columnar clay-bed may perhaps be a local development of that which forms partings in the limestone near Litton Tunnel.”

The generic and specific names and the horizons are those given by the authors. The numbers in square brackets correspond to those of the Museum register. A list of references and a history of the collections is given at the end. The localities, except where otherwise stated, are in Norfolk.

It is a well-known fact that many islands in which there is no indigenous mammalian fauna, have been, and in some cases are still, inhabited by flightless birds, which are usually of considerable size. Mauritius and Rodriguez are good examples of such islands; in the former the dodo and aphanapteryx, in the latter the solitaire and erythromachus, existed at least as late as the beginning of the seventeenth century, when, owing to their inability to escape from their foes by flight, they fell easy victims to the crews of ships touching at the islands, and also to the various domestic animals, such as dogs, cats, and pigs, introduced by man.

The discoveries and investigations of palæontologists touching the question of ambulatory and branchigerous appendages of the Trilobites have been entirely ignored by many of the ablest workers in the science. The important evidence which Mr. Billings produced was unsatisfactory to both Dana and Verrill. In 1881, after many years of untiring labour, Mr. C. D. Walcott (in the “Bulletin of the Museum of Comparative Zoology at Cambridge College”) furnished most conclusive proof of the existence of appendages to the cephalic, thoracic, and abdominal divisions of Calymene, Ceraurus, and Acidaspis. He says: “the discoveries have been received in about the same manner” as those of Billings and others—with incredulity, and as “having little value.”

The Geologists& Association has done a valuable service for British geology and for English-speaking geologists outside the British Isles by organizing field excursions and, for or from them, publishing guides. The first GA contribution was a report of a field meeting led by Gregory & Tyrrell (1924). In the 1960s there was a GA series of at least 41 guides covering most field areas in Britain and of these the one by S. I. Tomkeieff (1961) treated Arran. Tomkeieff's guide was brief and was not up to the standard expected of a work concerning this much frequented island. That work may be out of print and this guide appears to be a replacement. McKerrow & Atkins is good value and gives much to think about. Without hesitation, then, the reviewer's advice is that anyone going to Arran should buy it.

The petrogenesis of Palaeoarchaean mafic–ultramafic rock suites from the western Iron Ore Group, Singhbhum Craton, eastern India, has been evaluated based on the chemistry of constituent mineral phases. The rock suites include basaltic rocks and mafic (gabbro) to ultramafic (serpentinized peridotite) intrusive rocks, which occur in host rocks covering phyllite, ferruginous shale, banded haematite quartzite and jasper. The constituent clinopyroxene shows dominant uralitization, whereas plagioclase grains are generally saussuritized, being marked by relatively tiny granular aggregates of albite, chlorite, epidote and K-feldspar. The ultramafic intrusive rocks are overwhelmingly serpentinized. Clinopyroxene compositions are augitic, whereas relict plagioclase is typically bytownite. Amphiboles of the investigated rock suites are divisible into the ‘uralite’ type (occurring peripherally to clinopyroxene) and the ‘completely changed-over amphibole’ type (with no traces of initial clinopyroxene). Both the amphibole types belong to the ‘calcic group’, showing a compositional spectrum from actinolite–magnesiohornblende–ferrohornblende–ferroactinolite. Opaque minerals include magnetite (both Cr-magnetite and Al-magnetite), chromite (Al-chromite) and ilmenite, whereas serpentine (belonging to the ultramafic intrusive rocks) corresponds to lizardite. Looking at the mineral compositions of the pyroxene, glass and amphibole, the studied rock suites show a wide equilibration temperature–pressure domain range (∼750 °C to ∼1400 °C at ∼0.26 kbar to ∼21 kbar), which corresponds to an ascending magma that underwent a ‘hydration event’ at a shallow level. The assessment of the clinopyroxene and spinel chemistry characteristically suggests an arc setting for the parent magma that has undergone both equilibrium and fractional crystallization in the course of magmatic evolution. During differentiation, the magmatic density remains almost constant, with variable oxygen fugacity.