Showing papers in "The Journal of Geology in 1922"

A Scale of Grade and Class Terms for Clastic Sediments

Abstract: In no other science does the problem of terminology present so many difficulties as in geology. With the growth of knowledge in any field of investigation, men devise new terms or redefine old ones in the attempt to convey more precise and definite ideas. In all the branches of science much confusion has followed the redefinition of old terms because of the indiscriminate use of the terms both in the old and the new senses. But in geology, difficulties of this kind are peculiarly great. Because geology is a field science and has followed in the footsteps of exploration, it has acquired terms from all parts of the world. Many of the names for the less common special features have come from the dialect or colloquial speech of that part of the world where they are best developed. With the use of these terms of geologists of other regions, much irregularity of usage and hence much confusion has arisen. Since '917, the writer had been engaged in the study of abrasion and shaping of cobbles and pebbles by the action of running water. In the course of this study the loose usage of cobble, pebble, and related terms (in which his own practice was no exception) has impressed him with the need of greater uniformity of usage and

The Reaction Principle in Petrogenesis

Abstract: It is now many years since petrologists first began to think of the crystallization of a molten magma in terms of the physicochemical principles governing the behavior of solutions. In the study of ordinary solutions a condition frequently found was that known as the eutectic relation. In the simple case of two components, each lowered the melting-point of the other to the temperature of the eutectic point, at which temperature both solids separated side by side from a solution of fixed composition, the eutectic mixture. This case and the analogous condition in systems of more components are now so familiar to petrologists that they need not here be enlarged upon. The concept of the eutectic was early seized upon by petrologists and has been one of great utility in petrogenic theory. It accounted for the low melting temperatures of mixtures of minerals that are individually highly refractory. It threw light on some of the factors governing the separation of minerals from their mutual solution. But most of all, it stimulated the tendency to think of magmas in the light of the laws of solutions, or, better, of phase equilibrium, and encouraged experimental research whose expected result was the location of the composition of the eutectics for chosen mineral

The Behavior of Inclusions in Igneous Magmas

Abstract: Many igneous rocks contain inclusions of foreign material and not infrequently these inclusions show evidence of having been attacked by the magma, some to a moderate extent and others to such an extent that only traces of the inclusion remain. To some petrologists these inclusions are but the remnant of a great host, most of which has been completely incorporated in the magma, and to such incorporation or assimilation of foreign matter they would assign the principal variations of igneous rocks. The variations are not usually regarded by these petrologists as the result of assimilation alone but of assimilation followed by the differentiation of the syntectic magma which is supposed to have special powers of differentiation not possessed by the original magma. Other petrologists believe that magmas cannot be expected to have the energy content necessary for the solution of a significant amount of foreign material; that the amount of solution actually observed at and near contacts is an approximate measure of the total and that the variations of igneous rocks are quite independent of these slight additions, being due to spontaneous powers of differentiation possessed by original, uncontaminated magmas.

The Great Fault Troughs of the Antilles

Abstract: The region of the Greater Antilles is characterized by a marked elongation of the principal geographic features in an east-west direction and by extremely high relief (Plate I). The highest point above sea-level, Mount Tina on the island of Haiti, has an elevation of over 3,00oo m. while the deepest sounding in the Atlantic Ocean (8,526 m.) was obtained only 320 km. to the northeast.2 The Antillean mountain ranges are among the most precipitous in the world, but their slopes are, in large part, submerged beneath the surface of the Atlantic Ocean and Caribbean Sea. Off the north coast of St. Croix the descent is 4,348 m. in a distance of 8 km., and for shorter distances the slopes are very much steeper. The physiography of the Greater Antilles is very complex and as yet little of the region has been studied in detail. The dominant tectonic trend is approximately east and west along arcs convex toward the north, in part following the margins of the great troughlike depressions which are such a striking characteristic of the

On Contact Phenomena between Gneiss and Limestone in Western Massachusetts

Abstract: 'B. K. Emerson, "Geology of Massachusetts and Rhode Island," U.S. Geol. Surv., Bull. 597 (1917). In older papers by the same author, "Geology of Old Hampshire County, Mass.," U.S. Geol. Surv., Mon. 29 (I898), and "The Geology of Eastern Berkshire County, Mass.," U.S. Geol. Surv., Bull. I59 (1899), this granite gneiss is designated in part as "Becket conglomerate gneiss" and in part as "Tyringham gneiss."

The Character of the Stratification of the Sediments in the Recent Delta of Fraser River, British Columbia, Canada

Abstract: During the course of an investigation, carried on during parts of 1919 and 1920 by the Geological Survey of Canada in co-operation with the Department of Public Works, of the characteristics of Fraser River, British Columbia, an opportunity was afforded of studying the character and mode of origin of the stratification of the sediments forming the Recent delta of the Fraser. Bottom samples were obtained by means of a bottom-sampling machine which furnished core samples (i) from the sea-bottom deposits in the Strait of Georgia, and (2) from the fresh-water deposits in Pitt Lake, a tidal lake tributary to the Fraser. The object of this paper is to describe the character and mode of origin of the stratification of the Recent delta deposits of the Fraser River, and to contrast the character of the stratification of the sediments being formed in fresh water with that of the sediments being formed in salt water. The writer is indebted to Dr. W. Bell Dawson, superintendent of the Tidal and Current Survey, Department of the Naval Service, Canada, for information regarding the tides and tidal currents in Fraser River and in Pitt Lake, and to Mr. C. C. Worsfold, district engineer, Department of Public Works, Canada, for information regarding the tides and freshets in Fraser River.

Pennsylvanian Stratigraphy of North Central Texas

Abstract: The Pennsylvanian strata of north central Texas furnish a beautifully exposed and nearly complete section of the rocks of this period, exceedingly variable in lithologic character and prolific in well-preserved fossils. Yet because of their isolation and the semiarid, somewhat forbidding character of the country in which they outcrop, detailed study of them has been long delayed. The discovery in recent years of great deposits of petroleum within this area has brought to it many geological workers, and has served as a great stimulus to the study of the stratigraphy, differentiation, and correlation of its formations.

An Outline of the Geology of New Zealand

Abstract: Pre-Silurian.-In the more recent accounts of the history of New Zealand it has been customary to consider as of Pre-Cambrian age the complex of gneisses and associated metamorphic rocks in the southwestern extremity, but the evidence for so doing is not yet conclusive, and various authors have referred the plutonic gneisses therein to different periods, extending as late as the Cretaceous. It would appear that the more probable hypotheses could be limited to two. The first definite point lies in the proved existence of Lower Ordovician rocks in the extreme northwest and southwest of the South Island (Fig. i)." These graptolitic slates are associated

Post-Glacial Lakes in the Mackenzie River Basin, North West Territories, Canada

Abstract: It is a well-known fact that lakes or ponds of impounded water would form whenever the retreating continental ice sheet receded down a stream valley. It is therefore evident that the run-off from the eastward slopes of the Rocky Mountain cordillera would be impounded behind the retreating ice front of the Keewatin glacier as it receded, and the lakes so formed would expand laterally along the margin of the ice sheet, and the water would collect both from the inflowing streams and the melting ice until it rose above the lowest point in the stream valley walls, when it would spill over and form a new river course, possibly at considerable variance to the pre-established drainage lines. Thus we would expect to find evidence of ice-dammed lakes of greater or less magnitude throughout large areas in the northern portions of the great plains area of the Dominion of Canada. It is not the object of this paper to deal with the possible extent of such lakes throughout the northern regions, but rather to consider one or two specific stages in the lake expansions as they were apparently developed in the lower Peace and Athabaska river valleys, Athabaska Lake and Great Slave Lake.

Aspects of Ontogeny in the Study of Ammonite Evolution

Abstract: It is well known that the development of an individual generally recapitulates to some extent the stages passed through during the evolution of its ancestors, or in other words, that "ontogeny repeats phylogeny." In the paleontological work of the last quarter of a century this principle of recapitulation has frequently been used in determining the relationships of fossils, and its general truth has been demonstrated among many groups of Invertebrates; for example, by Mr. R. G. Carruthers and others among the Rugose corals,' by Professor Grabau among the Gastropods," and by numerous workers, particularly Mr. S. S. Buckman, among the

On the Occurrence of an Apus in the Permian of Oklahoma

Abstract: Professor J. W. Beede last year sent two specimens of a crustacean from the Permian of Oklahoma to the New York State Museum for investigation. They were from a suite collected by Dr. Thomas T. Jackson in a thin sandstone bed of the Enid formation, exposed "on the top of a hill four or five miles north of Elkeno, Oklahoma." The specimens' proved, on inspection, of exceptional interest for the reason that they not only exhibit an outline of the carapace as seen in Apus but even the impressions of the "shell-glands" or excretory organs in a form as it is today known in Apus, and its close relative Lepidurus. We have, therefore, no hesitation in considering this Permian form a true Apus, and propose for it the name Apus beedei sp. nov.

A New Phytosaur from the Trias of Arizona

Abstract: Among the vertebrate remains from the Triassic of the western states no other group is so abundantly represented as the Phytosauria. Relatively abundant as fossils of this group are, however, there is much to be learned of each of the several distinct types that have been described. For the most part it is the skull that is available for study, but even this is imperfectly known. Some time ago the writer described a well-preserved phytosaur skull from Arizona, now in the geological museum of the University of Wisconsin. This skull was considered a new form and was made the type of the genus Machaeroprosopus.' While several of the doubtful details of the phytosaurian skull were made known by the study of the specimen, especially the relations of the bones of the posterior side, the palate, as is usually the case, was left in doubt. Through the kindness of the University of Chicago the writer was permitted some time ago to study a phytosaur skull in the collections of Walker Museum; a skull very similar to the University of Wisconsin specimen in many points. The study of this material has made evident several pointed suggestions especially concerning the structure of the palate. The specimen herein described is No. 396 of the Walker Museum Vertebrate Paleontology Collections. It is the gift of Professor J. E. Anderson, formerly of the School of Mines, at Socorro New, Mexico. The name of the collector is unknown and the exact locality has not been recorded. However, the skull is known to

Intraformational Corrugated Rocks

Abstract: CONTENTS INTRODUCTION DIFFERENTIAL MOVEMENT ACCOMPANYING THRUST FAULTING DIFFERENTIAL MOVEMENT ACCOMPANYING NORMAL FAULTING DIFFERENTIAL MOVEMENT ACCOMPANYING REGIONAL FOLDING DIFFERENTIAL SQUEEZING ACCOMPANYING REGIONAL FOLDING DIFFERENTIAL MOVEMENT UNDER THE ACTION OF GRAVITY SUBAQUEOUS GLIDING OR SLUMPING ACTION OF ICE DIFFERENTIAL WEIGHTING CRYSTALLIZATION AND HYDRATION PRESSURE OF INTRUDING MAGMAS ACTION OF MAGMATIC INJECTION MAGMATIC FLOWAGE

The Hot Water Supply of the Hot Springs, Arkansas

Abstract: An investigation of the geology of the hot springs in the Hot Springs National Park was recently undertaken for the purpose of determining whether the supply of hot water can be increased. Some new facts were obtained, earlier work critically examined, and recommendations made. The problem is intimately related to the ultimate origin of the water. Thus an investigation begun solely for economic reasons led to a consideration of one of the most

The Muddy Mountain Overthrust in Southeastern Nevada

Abstract: Geologists have long recognized the fact that the region of the Basin Ranges has passed through more than one period of deformation since the middle of the Mesozoic era. The most recent important disturbance found expression chiefly in great normal faults, which divided the crust into essentially parallel mountain ranges. Within many of these mountain blocks the structure is complex. Tertiary formations are strikingly unconformable among themselves, and rest with profound unconformity on the older rocks. This great unconformity is a record of prolonged erosion following an epoch of crustal compression in Mesozoic time. The youngest rocks involved in this disturbance appear to be of Jurassic age; and therefore it is probable that the movement was contemporaneous with the folding of the Sierra Nevada and Humboldt Ranges. The degree of deformation due to this mountain-making varies greatly in the different ranges. In some the Mesozoic and older strata appear to have been nearly horizontal before the last important period of faulting. Other ranges preserve a record of the Nevadian movement in folds of varying intensity. In the Muddy Mountains of southeastern Nevada the record consists of overturned folds and an overthrust of considerable magnitude. These structural features were recognized by the writer in the course of field work during the summer of 1919, and a brief description has appeared in another article." The present paper will give a more detailed description of the overthrust (Figs. i and 2).

The Time of Glacial Loess Accumulation in Its Relation to the Climatic Implications of the Great Loess Deposits: Did They Chiefly Accumulate during Glacial Retreat?

Abstract: Although deposits similar in several respects to glacial loess are forming today near the borders of certain deserts and along the bluffs of some great rivers, the widespread, thick loess deposits which are associated with some drift sheets imply peculiar climatic conditions, for no deserts are now close to these ancient deposits, and parts of them are far from great rivers. There have been many discussions of the probable origin of loess, and thus, indirectly, of its climatic implications. Much has been learned, among other things that different deposits accumulated under different conditions. But one question appears not to have been satisfactorily settled, that is, At what time, in respect to glaciation, did the greater part of the accumulation take place ? Several American and European students have thought that the great loess deposits date from interglacial times. On the other hand, Penck has concluded that the loess was formed shortly before the commencement of the glacial epochs; while many American geologists have held that most of the loess accumulated while the ice sheets were at approximately their maximum size. Chamberlin and Salisbury,' McGee, and others lean toward this view. There is evidence in support of each of these hypotheses, but it seems well to reconsider the possibilities that a large share of the great deposits associated with glaciation were formed at the one other possible glacial time, namely immediately following the retreat of the ice. Recent evidence affords light not available to the workers

The Nephelite Syenite and Nephelite Porphyry of Beemerville, New Jersey

Abstract: During the earlier geological survey of New Jersey many outcrops of igneous rocks, mainly dykes, were mapped and recorded in the state reports without particular description. These rocks are nearly all located in Sussex County, and, owing to the small size of most of the outcrops, their scattered nature, the maturity of the topography, and the extent of weathering of the rocks themselves, their interesting nature has only been recognized gradually, though the first record of the largest mass dates back to 1868. Through the work of Emerson, Kemp, and Wolff these rocks are now widely known and are regarded in the local sense as a suite of genetically connected alkalic intrusions, and more generally as

A New Occurrence of Cristobalite in California

Abstract: Cristobalite, one of the rarer high-temperature forms of silica, was first described from the andesite of Cerro San Cristobal, near Pachuca, Mexico, by vom Rath,' and was established as a distinct mineral species by Mallard2 Artificial cristobalite has been prepared in the Geophysical Laboratory at Washington and its properties and its relation to the other forms of silica have been studied by Fenner3 Silica bricks are made up of artificial cristobalite and tridymite, and so these minerals are of some importance to the

Fault Features of Salton Basin, California

Abstract: The Salton Basin is a great natural depression in the southeastern corner of California (P1. I). Its lowest elevation is 273.5 feet below sea-level,2 and the lowest part of the basin is now occupied by the more or less ephemeral lake known as Salton Sea, which was created in 1905 by the accidental escape of Colorado River during the diversion of irrigating water to Imperial Valley. Physiographically, Salton Basin is continuous with the depression occupied by the Gulf of California, and the only topographic barrier that prevents the access of sea-water to the basin is a delta dam built up in recent geologic time by Colorado River. At its lowest point this dam is less than 50 feet above sea-level.

Dinosaur Tracks in Hamilton County, Texas

Abstract: Attention has been called by E W Shuler to the occurrence of dinosaur tracks in the Glen Rose limestone of Lower Cretaceous age, near the town of Glen Rose, Somervell County, Texas Another interesting occurrence of similar tracks has recently come to light in the extreme southern portion of Hamilton County, Texas, about sixty miles south-southwest of the first-mentioned locality (Fig I) The tracks in Hamilton County are also in limestone belonging to the Glen Rose formation They are exposed in the bed of Cottonwood Creek (Fig 2), a small headward tributary of Lampasas River, and are confined to a single stratum of rather soft, compact, yellowish limestone about a foot thick, which for a distance of probably 800 feet makes the bed of the creek In the Glen Rose locality the tracks were evidently made by one individual moving continuously in the same direction; but in Hamilton County they were made by a number of individuals, and the tracks point in every direction of the compass, this spot seemingly having been a favorite haunt of dinosaurs of every size and presumably,

Notes on the Sand Dunes of Northwestern Indiana

Abstract: Of the sand dunes of North America, few present more interesting phenomena than those bordering the southern shore of Lake Michigan. Not only do they illustrate all phases of dune activity but they have a significance in ecology and post-glacial history as well as rare scenic beauty. They are conspicuously developed in northwestern Indiana, their maximum development being confined to the 20 miles of shore between Gary and Michigan City. Heights of 1oo feet are common and the height of the frontal ridge along the lake commonly ranges from 75 to 175 feet. Parts of the dune complex are fixed and forested, while in other areas the sand is being shifted. The dunes are limited largely to a belt about a mile wide along the shore, although in places low dunes extend several miles inland. Along the western shore of Lake Michigan for 20 miles north of Chicago the waves are actively cutting into the thick drift, here composed of rather fine materials. This wave-cut cliff may be seen on the Highwood topographic map and in places is more than 80 feet high. A very considerable amount of erosion has taken place and some of the debris has been transported southward by the alongshore currents. Evidence of this movement is seen in the accumulations of sand on the northern sides of piers and the southerly deflectiofi of streams entering the lake where unprotected by breakwaters. With the wear and sorting involved in the transportation, the material which reaches the southern end of the lake is almost exclusively quartz sand. Here the topography and prevailing winds are such that deposition takes place. The shore sands become the prey of the winds and the dunes reach their greatest development. In order to examine the effect of the wind transportation on the sand grains, nearly fifty samples were gathered along seven lines

Origin of the Triassic Trough of Connecticut

Abstract: The paper by Professor W. M. Davis on "The Triassic Formation of Connecticut"' has long been regarded as a masterpiece in geologic literature. So well was the work done that little has been added to the knowledge of the Newark formation in Connecticut since its publication. Professor Davis did not, however, reach a definite conclusion concerning the origin of the trough within which the Newark sediments collected. Two hypotheses have been most widely held to explain the origin of the depression. It is the purpose of this paper to state briefly the field facts which bear upon these hypotheses and to suggest a method of research which may aid in the solution of the problem. The two hypotheses referred to are: (i) the depression was formed by a gradual bending downward of a canoe-shaped trough without faulting movements (Fig. i), and (2) the depression was developed by faulting movements on each side of the depression sedimentation (Fig. 2). Both of these hypotheses were suggested by Professor Davis in his report.2 The fundamental hypothesis may be modified by certain limiting conditions. Professor Davis was inclined to believe that the formation of the trough was not accompanied by faulting. He also held that the original area covered by the Newark deposit was not much greater than that over which the series outcrops today.3 Professor Grabau, while agreeing with Professor Davis in part, believes that a vast geosynclinal wedge extended from the eastern folds of the Old Appalachian Mountains, and that the present areas "are mere erosion remnants

Former Courses of the Androscoggin River

Abstract: The Androscoggin River is one of the most interesting of the many examples of disarranged drainage in New England and merits more attention than it has hitherto received. The present study has involved a critical examination of the topographic relations of the Androscoggin and several adjacent rivers, differentiating the topography controlled by underlying bed-rock formations from the topography of surficial deposits. Nearly all that part of the problem south and east of Berlin, New Hampshire, is covered by the topographic sheets of the United States Geological Survey; but the region north of Berlin is best shown on Hitchcock's map of New Hampshire;2 and, finally, the hydrography of the entire area included in this investigation is shown in outline on the accompanying drainage map (Fig. i).

The Structural Relation of the Purcell Range and the Rocky Mountains of Canada

Abstract: It has been found repeatedly, in recent years, that on the flanks of many elongated mountain ranges there are thrust faults dipping in under the range. In the absence of these faults, overturned folds, with their axial planes dipping into the range, and indipping slaty cleavage are common. Partly from observation of this sort, Dr. R. T. Chamberlin developed his hypothesis of the wedge-shaped zones of deformation in mountain building.' With this idea in mind, I attempted to determine whether the Rocky Mountain trench, a long, narrow depression between two mountain ranges, would show a connection with this type of structure. This great valley has a length of about 800 miles. It starts somewhat south of the boundary line between the United States and Canada and runs in almost a straight line to the northwest between the Rocky Mountains on the east and a succession of ranges on the west. From what is known about the trench it has been estimated to have an average width from wall to wall of 5 miles. The portion of the trench which I studied was from Gateway, Montana, at the boundary line, to Golden, British Columbia, 180 miles to the north. Study of the trench has been hitherto quite limited. Dr. Daly's section at the 49th parallel2 crosses the trench, Dr. Schofield's "Cranbrook Area"3 borders the west side of it for about 60 miles, and the section along the main line of the Canadian Pacific across the Cordillera, made by Allen and Daly,4 crosses it about 200 miles north of the boundary. Others have made rapid reconnaissances of the trench.

On the Representation of Igneous Rocks in Triangular Diagrams

Abstract: It has been customary to represent three components in a triangular diagram by a dot, or four components by a triangle within the triangle. The writer, by means of only a dot and a line, plots without the use of a slide rule or any calculation whatsoever, the actual percentages of quartz, orthoclase, plagioclase, and dark minerals as well as the relative percentages of quartz, orthoclase, and plagioclase among the light constituents. Let it be required to plot a rock with the following mode:'

An Outline of the Physiographic History of Northeastern Ontario

Abstract: The region here referred to as northeastern Ontario is one about 250 miles square, lying between Lake Superior and the Quebec boundary and reaching from Lake Huron north to the Transcontinental Railway Its topography has been described so many times in reports of the Geological Survey and of the Ontario Bureau of Mines that no extended account of it is needed in this place The region is referred to by geologists and topographers as a glaciated peneplain As a matter of fact it is a hilly country and only conveys an impression of flatness when a large area is seen at one time Viewed from the top of one of the more commanding hills the horizon appears as an even line and the intervening hills can be seen to stand at about the same elevation The rivers have slopes of only 5 to Io feet a mile, and the highest and lowest points on the railways which cross the region are 1,350 and 600 feet above sea This condition holds true for most of northeastern Ontario There are a few places, however, where the relief is greater, and where significant traces remain of a former topography of more rugged character There is, for example, one hilltop, about 40 miles west of Sudbury, from which one can see, on a fine day, a line of white hills on the southern horizon that certainly remind one of mountains These are the Lacloche Mountains, to which further reference will be made It also requires considerable scientific faith to acknowledge the wild country bordering Lake Superior as plainlike or nearly plainlike In the case of a true plain, like the Mississippi basin, or the western plains of Canada, the impression of tranquillity conveyed by the landscape is borne out by the rocky structure underneath