A discussion of geological description and an account of the Descriptive System LSDØ2 are given. It is shown that by examination of the aims of description and of its main instrument, the geological observer, a set of principles and objectives may be established in order to design descriptive systems. The application of these principles is demonstrated by an account of the theory and practical aspects of the Lithostratigraphic Descriptive System LSDØ2.

The composite granodiorite batholith of the Kopaonik Mountains forms one of the more southerly members of the peri-Adriatic tonalitic intrusions. In the area discussed in this paper it intrudes a series of sedimentary rocks which range from dominantly calcareous to pelitic types. Metamorphism of these rocks has produced crystalline limestones, skarns, and calc-silicate hornfelses, which grade downwards into mica-, amphibole-, epidote-, and locally cordierite-bearing rocks. The pelitic and amphibole-bearing hornfelses are in immediate proximity to the batholith on the surface. The amphibole-bearing types are mainly confined to a relatively small area, well within the zone of high-grade metamorphism and overlying the southerly pitching nose of the intrusion. With them are associated hornfelses which carry porphyroblasts of albitic feldspar. It appears that the persistence of the amphibole and the development of these feldspar porphyroblasts may have been caused by hydrous and probably sodic emanations which permeated the sediments above and ahead of the advancing igneous mass.

Several sag-type basins apparently developed from rift systems, but there is no consensus about how and if these grabens influenced the sedimentation of the post-rift thermal subsidence phase. The Ediacaran Jaibaras Rift Basin is one of the best-exposed sedimentary records among the NE Brazil late Precambrian – early Cambrian rift system, cropping out at the eastern margin of the intracratonic Parnaíba Basin and extending below it towards the west. Here we present detrital zircon U–Pb ages of rocks from the Jaibaras (Aprazível Formation) and Parnaíba (Ipu Formation) basins, in order to understand the provenance patterns, maximum depositional ages (MDA) and age relationship between these units. The MDA for the Aprazível Formation (c. 499 ± 5 Ma) indicates a Cambrian age for the upper part of the Jaibaras Basin. The bulk U–Pb data indicate that the Ipu Formation started to deposit during late Cambrian and/or Early Ordovician time, despite its MDA (c. 528 ± 11 Ma) being older than that of the Aprazível Formation. Detrital zircon provenance suggests that the primary source areas for the early deposits of the Parnaíba Basin were mountains related to the Brasiliano Orogeny to the south and SE (e.g. Rio Preto and Riacho do Pontal metamorphic belts). Finally, our data emphasize the key change in source areas from the rift to the initial deposition of the intracratonic phase, indicating major depositional style changes between both basins after the Gondwana assembly.

Comparatively few of the many persons who visit our larger Museums, and stop to examine the fossils exhibited in the cases, have any idea of the time, labour, care, and mechanical skill which many of them require ere they are ready for the palæontologist to interpret and describe, the artist to delineate, or made sufficiently intelligible for public exhibition. The first operation, and one requiring considerable care, is the exhumation of the fossil remains from the stratum of gravel or clay, or from the siliceous or calcareous rocks of various degrees of hardness, in which they may have been imbedded and preserved. Then the hardening of the bones—for these remarks apply more especially to the remains of the larger Vertebrata—which are generally found much broken, and, unless thoroughly mineralized, in a more or less friable and brittle condition. Next there is the fitting and cementing together of the pieces, which are frequently numerous, and of such as have been imbedded in a rocky matrix, the careful development by hammer and chisel from their incasement of stone: all of which operations necessarily involve a large amount of skilled labour.

Having some time since been favoured by Mr. and Mrs. Coomáraswámy (Miss Ethel M. Partridge) and Mr. Joseph G. Hamling, F.G.S., of Barnstaple, with the loan of their collections of Culm Trilobites from Coombe Wood, etc., near Barnstaple, I feel it incumbent to add a few notes to those already published by me in the Appendix to Messrs. Hinde & Howard Fox's paper (Quart. Journ. Geol. Soc., 1895, vol. li, pp. 646–649, pl. xxviii, figs. 1–8).

The costellae of a population of brachiopods can be quantitatively described by plotting the total number of costellae on a valve against the length of its margin. The resultant curve describes the continuous change of the average distance between adjacent costellae during growth. When costellae first appear, this distance has the value of about 0·06 mm and it increases during growth to various degrees in different brachiopod species.

If it is assumed that costellae mark the sites of setae, then the magnitude of the distance between adjacent costellae can be discussed in terms of the function of setae.

The magnitude of the parameters of the distribution of setae and punctae are compared to the silt/sand dividing line.

An extensive study of the microstructure, nanostructrure and crystallographic properties of six taxa belonging to four different genera of Devonian and Carboniferous Syringoporicae showing dense phaceloid (Pleurosiphonella), pseudocerioid (Neomultithecopora) and cerioid growth patterns (Roemeria and Roemeripora) has been done in order to disclose the similarities and differences in the growth processes at the biomineral scale and understand the growth processes that provide organisms with an evolutionary advantage to colonize different habitats. All the skeletons have similarities regarding the biocrystallization process, showing that the Syringoporicae skeletons are a product of matrix-mediated biocrystallization. Micro- and nanotextural features are common in all of the skeletons studied, showing that they were composed of hierarchical structures. All studied taxa possess a complex nanostructure composed of co-oriented rounded nanocrystals with different sizes and morphologies, depending on the taxon. The identified microstructures include granules, lamellae, fibres and hyaline elements. The crystallographic techniques demonstrate that all of them except the hyaline elements are biogenic in origin. Granules could be aborted fibres during the growth of two corallites in contact. On the other hand, the study of the biomineral properties suggests that the skeleton structure is a reflection of the genetic code. The median lamina was formed by the joint crystallization of both polyps at the same time. The variation in the internal structural organization (phaceloid, pseudocerioid or cerioid) was conditioned by the environment (stressful situations or feeding strategies); on the contrary, the final structure is controlled by genetics and their crystallographic properties are characteristic for each internal structural organization.

In an article with the foregoing title (Geol. Mag., Vol. LXVII, 1930, page 97) some unfortunate errors of statement, in part quite unaccountable, were printed.

Studies on type-V fulgurites are very sparse in the literature. This work reports on the characterization of natural exogenic fulgurites found at the archaeological site of Cerro de la Ermita (Tiedra, Valladolid, Spain), which was firstly a Celtiberian and then a Roman locum sacrum. Data from X-ray powder diffraction, X-ray fluorescence spectroscopy, Fourier-transform infrared spectroscopy and Raman spectroscopy suggest that the fulgurites consist of naquite, piroxenes, iron oxides, shocked quartz and neo-formed cristobalite.

An attempt has been made to show that basic magma is associated with vertical and not with folding movement, that basic intrusions take the form of those characteristic of unfolded regions and of relatively high levels and that differentiation in situ is common.

It is argued that basic magma is emplaced in the orogenic belts as flows and typically non-orogenic intrusions during the geosynclinal or sinking phase of the orogenic cycle, that rocks of the appinitic suite, which commonly occur as stocks associated with granodiorites, are formed from these non-orogenic basic rocks by a process of hybridization during a subsequent folding phase, but that no further basic magma is introduced during this phase.

It is suggested that the terms Non-orogenic Association and Orogenic Association might replace Volcanic Association and Plutonic Association to indicate the relation of basic and acid magmas to their tectonic environment.

Polypary slender, several inches in length, distal portion straight, proximal portion sharply recurved. Hydrothecæ 20 to 25 to the inch, in contact at their bases only; narrowing in the direction of the apertural portion, which is curled up into a rounded lobe.