In the Eastern European region Vendian strata are divisible into two complexes: the lower one, only locally developed, is composed of alternating tillites, volcanics, sandy–clay rocks and dolomites; and the upper one, of alternating sandstone, siltstone, and mudstone strata with medusoid fauna, resting transgressively on the lower complex and older rocks. The lower complex is associated with sheet glaciation; the upper one was formed in a post-glacial isostatic basin. The name ‘Vendian’ should be applied only to the upper complex; the lower one should be called ‘Waranger’.

The way in which probability can enter the interpretation of geological data is outlined. Probabilistic models are introduced in data synopses to allow statistical inferences about samples and population parameters. Inferences of this type are a special application of mathematical theory and have little to do with testing scientific generalizations. The logic of statistical inference, as used in operations research, is contrasted with that of geological inference. Geology is a cumulative science; its methodology is not that of experimentation with formal replication; inferences are developed from observations and tested and refined against new data, often by different investigators at different times and in different places. Because of the way in which inferences are drawn, sampling in geology is purposive. Random sampling, necessary for inferences based on sampling theory, is unattainable in most geological contexts. Different classes of geological measurements require careful consideration as to their appropriate form of synopsis, and, particularly, as to whether a parametric probability model is applicable.

The earliest skeletal microfauna of Precambrian-Cambrian age recovered from the ‘Lower Tal’ sequence (Chert-Phosphorite to Calcareous members) of the Tal Formation, exposed in the Ganga Valley, Lesser Himalaya, Uttar Pradesh, India, has been grouped into three assemblages. In ascending order these are: assemblage I, containing Anabarites trisulcatus Missarzhevsky, Tiksitheca korobovi (Miss.). Circotheca sp., Turcutheca sp., Spirellus columnorus Jiang and Olivooides alveus Qian; assemblage II, yielding Allonia erromenosa Jiang, A. sp. cf. A. erromenosa Jiang, Dimidia simpleca Jiang, D. sp. cf. D. simpleca Jiang and Hyolithellus sp.; and assemblage III, comprising Pelagiella lorenzi Kobayashi, Auriculatespira madianensis Zhou & Xiao and A. andunca He & Pei. The assemblages I and II are correlatable to the Meishucunian Zone I and Zone III respectively, and the assemblage III to the Qiongzhusian Stage of China. Thus the ‘Lower Tal’ sequence is assigned to Precambrian–Cambrian age.

The new terms ‘equal fold’ and ‘unequal fold’ are defined by whether the ratio of dips of limbs, measured in degrees, is less or greater than 1½.

SIR - Squire (1973) described and figured fossil burrows, ascribed to Sabellarites, from the Upper Proterozoic Brioverian Jersey Shale Formation of Jersey, Channel Islands. The meander-like structures are from calcisiltite beds within a turbiditic sequence and were collected from low intertidal reefs. Re-examination by all of us of one of Squire's specimens (Jersey Museum, La Hougue Bie, SJM C 2026; Squire, 1973, plate 1 a) and more decisive material (SJM C 1002, 5 specimens), collected later from the same reefs by Stéphane Rault, confirms that the structures are attributable to modern polychaetous annelids, almost certainly to Polydora sp., an attribution with which Dr J. D. George (Head, Polychaeta Section, British Museum (Natural History)) concurs. Polydora is associated with a wide range of substrate preference, constructing borings in hard calcareous substrates, pseudoborings on the inside of shells and true burrows in loose sediment. In the Jersey material the irregular, but quite typical, U-form tubes have been formed along open joint planes with slight dissolution of the rock, or along thin calcite-filled veins, also with dissolution of the rock. The joints occur at all angles to the bedding. Very pertinent is the attitude of the tubes, which is principally normal to the rock surface rather than to the bedding. No tubes have been seen on freshly broken surfaces and in no instance has a tube been seen to enter the rock, though there are numerous moulds of pyritic concretions which happen to be of about the same diameter as the width of the tubes. Lithothamnium sp. is patchily distributed over the rock surface and locally penetrates into the joints, showing that they were open.

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.