bluuebunny/crossref_metadata_2025_split huggingface dataset:
An early Ordovician shore-line in Radnorshire, near Builth Wells
Authors: Jones Owen Thomas , Pugh William John 
Published: October 2009

Summary
This paper deals mainly with the western margin of the Builth-Llandrindod Ordovician inlier and is concerned with the phenomena associated with the unconformity between the Newmead Series and the underlying Builth Volcanic Series. The rocks dip westwards and strike approximately north and south. They are extensively faulted and, in particular, the outcrops are displaced by powerful tear-faults.

The Newmead Series consists of Grey Felspar Sands, Pyritous Felspar Sands and the flinty mudstones of Tan-lan. Within the sands, and especially in the lower part of them, there are many impersistent boulder-beds; both these rocks are beach deposits. There is progressive overlap within the Newmead Series, so that ultimately the flinty mudstone rest directly upon the Builth Volcanic Series. The Newmead Series is followed unconformably by the
Glyptograptus teretiusculus
shales. A rhyolitic series emerges from beneath the
G. teretiusculus
shales near Cwm-amliw and can be traced into the northern part of the inlier.

The Newmead Series oversteps different divisions of the Builth Volcanic Series, the succession in the latter being most completely developed in the southern part of the inlier. The contact between the two series reveals the characteristics features of a coast-line, with wave-worn surfaces, sea-cliffs, screes and stacks as well as the beach deposits which occur in the Newmead Series. It is possible to reconstruct in detail the features of the area exposed to sub-aerial and marine erosion which was subsequently buried beneath the Newmead sediments. It consisted of horizontal layers of spilitic rocks, making trap topography, and in one locality this was overlooked by rounded hills of keratophyre. The presence of several outliers of Newmead sands to the east of the main outcrop indicates that the deposition of the Newmead sediments was probably widespread over most of the southern half of the inlier.

From our observations, it is possible to interpret the general sequence of events, in particular of elevation, erosion and depression. It is shown that all these events took place within a relatively restricted part of the time-interval represented by the
Didymograptus murchisoni
zone. Finally, attention is called to the remarkable preservation of these ancient Ordovician physiographical features.
The Lower Carboniferous reef limestones of Cracoe, Yorkshire
Authors: Bond Geoffrey 
Published: October 2009

Summary
The limestones forming the " reef-knolls " in the Cracoe district of Yorkshire lie at the eastern end of a belt of similar limestones which stretches westwards across the Central Province of the Carboniferous Limestone Series. This " reef belt " separates areas of contrasted sedimentation, the strata to the north being of massif (Great Scar) facies, while to the south lies the much thicker basin facies, of impure limestone with much interbedded shale. The Cracoe knolls have attracted much attention in the past, owing to their peculiar topography and the abundance of their fossils. Theories on their origin were based either upon supposed quaquaversal dips of original deposition or upon more normal deposition, followed by tectonic deformation and subsequent erosion.

It is now shown that the limestones in the Cracoe area are divisible into local faunal and lithological subdivisions, which can be mapped by the usual methods. These subdivisions are correlated with the coral-brachiopod zones and goniatite succession of the Viséan, and extend from S
2
to D
2
. The peculiar facies is due to the beds having been laid down against a long narrow ridge which kept the basin and massif areas of sedimentation apart until it was finally submerged in D
2
times, when sedimentation became continuous across it.

The reef limestones are, in fact, the marginal facies of the Great Scar Limestone, and the lateral change of each member of the local subdivision is traced through the marginal facies into the normal Great Scar Limestone.
The structure consists of a series of anticlines and broader synclines, arranged in echelon, which pass obliquely across the facies belts and die out north-eastwards. They were formed by pressure from the south impinging obliquely on a ridge of older rocks. The folding took place under exceptionally light cover and was completed before the Bowland Shales were deposited. The knoll topography was blocked out by faults which cut across the fold axes. The knolls themselves were eroded to very much their present shapes before the Bowland Shales, which lie with strong unconformity on the limestones, were laid down. The removal of these shales is now proceeding, and is re-exposing the buried topography of the knolls.
A tectonic window in south-western Iran
Authors: Gray Kenneth Washington 
Published: October 2009

Summary
The paper presents evidence of large-scale overthrusting during Upper Cretaceous times in part of the Zagros Mountains in south-western Iran. Thrust-sheets made up mainly of radiolarian cherts and serpentinous igneous rocks, and including fossiliferous rocks of Triassic age, are shown to have been extensively overthrust upon Cretaceous rocks, including Cenomanian limestones and marlstones probably of Senonian age. Marine Maestrichtian and younger rocks were deposited upon the thrust-sheets and were later folded, together with the sheets themselves and the underlying autochthonous rocks. Subsequent erosion of the cover has exposed the thrust-sheets over wide areas and in places has exposed the underlying autochthonous rocks in tectonic windows of which a striking example, the Dalnashin Window, is described in the paper.
Foraminifera from the Upper Lias of Byfield, Northamptonshire
Authors: Barnard Tom 
Published: October 2009

Summary
The paper, which for the most part is a systematic description of the foraminifera, is an attempt to unravel the somewhat complicated taxonomy of the species present. The foraminiferal fauna is unlike that of the preceding Lower and Middle Lias, being typically Upper Lias in appearance, except for several long-range species.
In the chapter on systematics the variation of several species is dealt with. On the whole, the foraminifera are very variable and some abnormal specimens occur.
Some aspects of magmatic evolution
Authors: Tilley C. E. 
Published: October 2009

Summary
The address is concerned with some aspects of magmatic evolution in volcanic successions, and includes particularly a discussion of the nature and genetic relations of primary and derivative basic and intermediate magmas.
Among the volcanic associations of the oceanic areas, those of the Hawaiian archipelago provide data of critical importance in the study of basaltic evolution. The established chronological succession of magmas in these islands makes it probable that the alkali-poor tholeiites to be recognized in the lavas of the primitive shield volcanoes form the closest approach to the primary magma of the ocean basins, and from them derive by fractional crystallization processes the Hawaiian alkali magma series of alkali olivine-basalt, mugearite (so-called andesite) and trachyte.
The course of volcanic variation there exhibited provides a new orientation to the study of the genetic evolution of the Tertiary igneous Brito-Icelandic province, and leads to the conception that the Hebridean alkali magma series derives through tholeiites as an alternative line of descent.
The course of fractional crystallization of tholeiite magma in the great layered intrusion with its final product of granophyre is illustrative of the great flexibility in line of descent which fractionation processes permit. Derivation by crystallization differentiation in a convecting system comparable to that demonstrated in layered intrusions seems, indeed, the most likely mechanism for the genesis of the primitive sialic layer of the crust itself.
The problem of intermediate magma in the volcanic successions of the orogenic belts is critical in petrogenic theory. Though fractionation processes appear most competent to give a liquid line of descent through andesite to rhyolite, normal andesite magma does not reflect in its chemistry the course of basaltic (tholeiitic) differentiation.
Consideration is devoted to the conception that andesites, though ultimately of basaltic parentage, have derived in part by sialic contamination.
The testing of the genetic relations of assemblages within the basalt-andesite range of the volcanic suites of the orogens remains one of the most important problems of volcanic petrogenesis.
Systematic attack through intimate phase analysis and geochemical study may provide the data which will go far to solve, not only the status of the voluminous andesite, but of intermediate magma in general in igneous rock evolution.
Graptolites from the
Dictyonema
Shales of Quebec
Authors: Bulman Oliver Meredith Boone 
Published: October 2009

Summary

The fossiliferous
Dictyonema
Shales of Matane are represented in older collections by a rich graptolite fauna which is here fully described on the basis of material sent to Lapworth at the end of last century, and the Richardson collection and other material from McGill University, Montreal. Included in this fauna is
Dictyonema canadense
(figured but not described by Lapworth) and four new species of
Dictyonema
, together with six species and varieties of
Anisograptus, Triograptus
and
Staurograptus,
and a species of
Didymograptus
. From other less fossiliferous localities spread along the south shore of the St. Lawrence River come some of the above, with another new species of
Dictyonema
, a
Bryograptus
and a monotypic new genus
Radiograptus
, intermediate between
Anisograptus
and
Dictyonema
. The stratigraphical relations of these various localities are unknown, but the whole constitutes a fauna of Tremadoc age which is assigned either to the highest part of the
Dictyonema
Shales (of Scandinavia) or the lower part of the Upper Tremadoc.

Structurally, all the species of
Anisograptus
, the
Bryograptus
and the
Staurograptus
are shown to possess stolothecae, and bithecae can be identified in most of them; the occurrence of this dendroid branch structure is also believed to characterize
Triograptus
and
Radiograptus
. Accordingly, all these genera, together with
Clonograptus
and
Adelograpius
, are separated from the Dichograptidae where they were previously placed, and united into a new family, the Anisograptidae, which is transferred to the Dendroidea. No phylogeny can be indicated with any assurance, but the whole group seems to constitute a plexus intermediate between the Dendroidea and the Graptoloidea.
The study of the world's plainlands: a new approach in geomorphology
Authors: King Lester C. 
Published: October 2009

Summary
A review of the older plainlands and plateaus of the earth reveals a similarity in age and elevation sufficient to suggest that their independent origin and development in their present situation is unlikely. It is claimed that continent-wide bevelled surfaces have been produced by " pediplanation ". A world-wide correlation of pediplaned surfaces now standing at varying levels above O.D. is suggested by the following grouping : (a) pre-Cretaceous super-continental cycles of erosion (" Gond-wana " and " Laurasia " surfaces); (b) pre-Miocene intermediate continental cycles (" African ", " Prairie " etc. surfaces); (c) modern continental cycles. The difference in elevation between the fundamental surface (a) and the plains of the continental early-Tertiary cycle (b) is attributed largely to the altitude of the twin Gondwana-Laurasia super-continents at the time of their break-up. It is suggested that global forces, and probably continental drift, must be invoked in explanation of these world-wide pediplaned surfaces.
Note on the gravel deposit from which the Piltdown skull was obtained
Authors: Edmunds Francis H. 
Published: October 2009

The age of the Piltdown skull has long been a subject of intermittent controversy and it is a question which can only be determined from palaeontological data or other evidence inherent in the fossil itself, such as that provided by fluorine fixation; details of river-terrace forms and levels as related to the present-day
thalweg
of the River Ouse, and of materials comprising the gravel in which the skull was found, offer little assistance.

In the literature on the subject some misunderstanding has arisen as to the height of the gravel deposit in which the skull was found relative to the present-day River Ouse; height above the river having to some extent been used to date the fossil.
According to levels taken from the six-inch scale Ordnance Survey map, Sussex 40 NE., the 100-foot contour above Ordnance Datum cuts the surface of the gravel spread, the highest part of which lies about 103 feet O.D. while the lowest part is about 97 feet O.D. The nearest part of the River Ouse, at Gold Bridge, is between 45 and 50 feet O.D. Thus the terrace is is about 50–55 feet above the nearest part of the river.
Dawson (1913, p. 119), however, stated that the terrace lies on a plateau above the 100-foot contour, with an average height of about 120 feet above O.D.; a statement true of the plateau, but not of the gravel terrace, which is the thing that matters. Again, he gave the height of the gravel spread above
Notes on the geology of the St. Elias Range, Alaska-Yukon Territory, North America
Authors: Odell N. E. 
Published: October 2009

The following notes are a preliminary record of geological results of work in the Yukon-Alaska boundary region by the writer with the expedition of the Arctic Institute of North America (project " Snow Cornice ") during the summer of 1949.
Field-work was mainly along the northern border of the great inter-montane basin occupied by the Seward Glacier (or firn-field), which lies intrenched behind, and immediately north of, the main St. Elias Range, of which Mt. St. Elias itself, 18,008 feet, is the dominant peak. During flights from the coast at Yakutat to and from this basin, and on other occasions over neighbouring localities, visual observations of structure and morphology were also made. Chiefly, however, field-work was a matter of climbing (as in the case of a pioneer ascent of Mt. Vancouver, 15,800 feet), or of skiing over the immense spaces of the Seward firn-field (750 square miles in area) in order to visit scattered island outcrops or mountain cliffs flanking the firn-field.
The region is underlain by a metamorphic series of sedimentary origin, mainly pelitic, with subordinate psammitic elements and marked calc beds. The pelitic series consists mostly of biotite-schists and gneisses, rarely garnetiferous; the calc beds are composed of fairly pure marbles, which occupy no regular stratigraphical position within the pelites, but occur in mountain walls as conspicuous elongated or irregular masses, having suffered severe deformation during orogenesis. The thickness of this whole series, whose dip is variable and locally vertical, was not determinable. Into the series has been
A tectonic window in south-western Iran.
Authors: Gray K. W. , Lehner E. 
Published: October 2009

From
Dr. E. Lehner :—

The peculiar conditions in the Niriz region, and especially at Kuh-i-Dalnashin, afford apparently unassailable evidence of the existence of a nappe of radiolarites and green rocks which was formed in Upper Cretaceous time. From my knowledge of published papers and of unpublished reports by the geologists of the Anglo-Iranian Oil Company I believe that, for the whole disputed zone from Oman to the Mediteranean, no other case of equal merit has been made out in favour of such a nappe. It is therefore desirable that Dr. Gray's conclusions be put to every test.
The paper does not explicitly deal with the roots of the composite radiolarite-green igneous nappe. It describes, however, in some detail the stratigraphical succession in the “Late Tertiary Overthrust Zone” and its south-eastern extension at Aghirq. Here the radiolarites are only thinly developed, as intercalations in the sandstones which mark the coming in of the Kirman facies of plant-bearing Jurassic. It would, therefore, seem obvious that the roots of the nappe must be looked for to the south of this zone, either in the Dehbid valley, which is covered by Neogene or Quaternary, or in a region now overridden by the late Tertiary thrusts. Yet in the sections (pl. ix) the Dehbid valley is shown as a gently folded monocline, and the drawing of the thrust zone does not admit the probability of a root zone underneath. Where does Dr. Gray assume the root to be ?
The paper tentatively suggests a
The mineralogy of some Nile sediments.
Authors: Shukri N. M. 
Published: October 2009

Dr. Shukri's reply to the discussion (pp. 530-4) ::—
The author thanks the speakers for their kind remarks and for their interest in the work. He also thanks Dr. Sandford for his answers to the questions raised. He fully agrees with Dr. Sandford that the Blue Nile and Atbara sediments were not added suddenly to the Nile system. Their material appeared for the first time in Lower Palaeolithic terraces and were absent in Pliocene and Plio-Pleistocene sediments.
In reference to Dr. Wiseman's remarks, the author states that local contamination is observed at present along the course of the Nile and is not restricted to the cataracts. Some of the Nile sediments in Egypt, for example, contain Nummulites and other fossils derived from the sedimentary formations north of the first or Aswan cataract. These, and any other material brought from the neighbouring deserts by wind or by casual torrents, are, however,of negligible importance in the recent sediments, as can be seen at present. The mechanical constitution of the sediments was determined and the clay fractions were investigated and the results will be given elsewhere.
In reply to Mr. Edmonds, the genetic significance of the uncommon minerals which are liable to spice the assemblages of the commoner minerals was taken into consideration in the paper. Some of these very scarce minerals are recorded as one grain in one slide out of five. On the other hand, the author sees no objection to the use of the more abundant minerals as evidence in
A contribution to the study of the Eocene in western Pakistan and western India: A. The geology of standard sections in the western Punjab and in the Kohat district
Authors: Eames Frank Evelyn 
Published: October 2009

Summary
Detailed descriptions are given of the geological successions in the Eocene of standard sections in the Rakhi Nala and at Zinda Pir in the western Punjab, and at Tarkhobi, Panoba, the Shekhan Nala and Sirki Paila in the Kohat district. The work forms the first stage in the reinvestigation of the classification and correlation of the Eocene in western Pakistan and western India. Comprehensive collections of fossils were made.
A contribution to the study of the Eocene in western Pakistan and western India: D. Discussion of the faunas of the certain standard sections, and their bearing on the classification and correlation of the Eocene in western Pakistan and western India
Authors: Eames Frank Evelyn 
Published: October 2009

Summary
Local palaeontologieal subdivisions are established for the Eocene of the Rakhi Nala, Zinda Pir and Kohat areas as a result of the examination of extensive collections of fossils recently made in these areas. The distribution of the different phyla in various facies developments is discussed. Comparison is made with the pre-existing major subdivisions of the Eocene in western Pakistan and western India. In the Rakhi Nala and Zinda Pir area, it is concluded that the Khirthar-Laki boundary has previously been taken at too low a horizon, and that beds previously referred to as lower Middle Khirthar include representatives of the upper Middle Khirthar, the Upper Khirthar, and still younger horizons of Upper Eocene age.
The lithological and mapping evidence and the palaeontologieal evidence from the Rakhi Nala and Zinda Pir areas are each considered separately and finally synthesized in order to arrive at as precise a correlation as is possible. The evidence from the Kohat Eocene beds has been synthesized with that from the Rakhi Nala-Zinda Pir area in like manner, and it is evident that only the major palaeontological subdivisions can be correlated.
The present investigations have confirmed the usefulness of the terms “Ranikot Series”, “Laki Series” and “Khirthar Series” for subdivisions of the Eocene in western Pakistan and western India. The writer considers that the basic and fundamental soundness of these terms is not affected by the fact that beds and faunas have occasionally been incorrectly allocated to one or other of them.

Certain beds, which are here named the “ Tapti Series ”, and which are not of very widespread occurrence, contain a fauna which is distinct from that of the Khirthar Series below and is of Upper Eocene age. The fauna of this series, in addition to several species of Upper Eocene age and a number of new species, includes the genus
Pellatispira
, which is also of Upper Eocene age and has not yet been unquestionably recorded from horizons as low as those containing the genus
Assilina
.

A consideration of all the available evidence indicates that published information concerning the ranges of some species is incomplete and that in some cases the existing conception of a species requires modification. The author is of the opinion that the “ zones ” which have been previously proposed within the Ranikot, Laki and Khirthar Series are of local rather than regional value, and that there has been too great a readiness to assign regional chronological significance to local facies faunas. It is evident that further work is necessary before regional zoning of the series can profitably be attempted.
The geology of the Arnage district (Aberdeen-Shire) : a reinterpretation
Authors: Read Herbert Harold , Farquhar Oswald Cornell 
Published: October 2009

Summary
In 1923, Read considered that in the Arnage district an initial gabbroic magma had been contaminated by country-rock material to produce on consolidation quartz-biotite-oligoclase-cordierite rocks (Arnage Type), pseudo-dioritic rocks (Kinharrachie Type) and finally granitic rocks (Ardlethen Type). Detailed field investigation leads to a new interpretation. The continuous magmatic series proposed by Read has been broken into two parts :—
1. An older part, consisting of the Arnage-Kinharrachie-Ardlethen types, produced by migmatization and comparable with migmatitic complexes of “ Older Granite ” age developed elsewhere in Aberdeenshire.
2. A newer part, gabbroic in character and belonging to the basic phase of the “ Newer Granite ” igneous activity of North-East Scotland.
The “ Older Granite ” migmatites of Arnage have characters, such as the hornfelsic nature of their enclaves and their richness in cordierite, that are appropriate to their setting in the metamorphic zones of North-East Scotland. They present a contrast to the Cromar type of migmatites set in the Barrovian metamorphic zones of the South-East Highlands.