Mountain Mass Research Articles

Three Hill Forts in Eastern Spain

The mountain known as Mongó is an isolated mass of limestone, rising to a height of over 2500 feet above the level plains which border the sea in the neighbourhood of Denia in the ancient territory of the Contestani and the modern province of Alicante (pl. I). Standing free, as it does, from the main mass of mountains, it is the most conspicuous landmark on the promontory which stretches eastwards towards the Balearic Islands. The views from its summit cover a wonderful expanse of country; south and westwards to the mountains, northwest across miles of orange groves to the coast leading to Valencia and beyond (pl. 6), while eastwards the Isle of Ibiza is clearly visible 70 miles away.

Age of the Folding of the Oklahoma Mountains--the Ouachita, Arbuckle, and Wichita Mountains of Oklahoma and the Llano-Burnet and Marathon Uplifts of Texas

Introduction This paper discusses the folding, in Carboniferous time, which resulted in the Ouachita, Arbuckle, and Wichita Mountains and the Llano-Burnet and Marathon uplifts (see figure 2). A new name, the Oklahoma Mountains; is introduced to designate all these ranges. 3 The Ozark Mountains are not included because they are essentially a part of a broad dome that extends from southeastern Missouri far west into Oklahoma, and that has undergone, uniformly, throughout its extent, broad periodic tilting and gentle folding unlike the sharp folding of the mountain masses on the south. Llanoris 4 is discussed because of its bearing on the folding of the adjacent mountains. Only the movements in Carboniferous time are considered. Earlier movements in southern Oklahoma, except, possibly, an upwarp of the western part of the Wichita Mountains, were of minor effect. In the Arbuckle Mountains the top of the Hunton limestone is in places missing and its . . .

Among the Kara-Korum Glaciers in 1925

KARA-KORUM is the name of a pass, yet it has been applied not only to the range containing the pass, but also to a tangled mass of mountains lying far to the west. Exploration of this tangle has indicated that it consists of a series of ranges; so that the name Kara-Korum, as it is generally used, indicates a large district, rather than any particular range of mountains.

Heavy-Mineral Data at the Southern End of San Joaquin Valley

Results of a brief heavy-mineral investigation are offered here as a supplement to a contemporaneous paper by R. D. Reed and J. P. Bailey. It is shown that distinct stratigraphic variations in heavy-mineral content occur in late Tertiary sediments of the San Emigdio foothills, sediments which, from all indications, have been eroded from a single mountain mass of comparatively uniform petrographic character. It is concluded, therefore, that the practical value of heavy minerals for correlation is not restricted to conditions under which sediments have been derived from two or more petrographically distinct sources.

Excessive cases of lateral refraction

Lateral, or horizontal, refraction is quite frequently encountered in the angular measurements of triangulation systems, but its occurrence is usually spasmodic and may usually be attributed to air currents or pockets on lines in proximity to buildings, mountain masses, etc. Two cases of consistent lateral refraction have occurred in Canada which permit the underlying causes in these cases to be investigated and, perhaps, explained.An extended and persistent example of lateral refraction was met on the triangulation net of the St. Lawrence River and Gulf, the field work of which covered some 325 miles and extended over four seasons. In this net the lines along the river bank were so consistently “bent” towards the river that a practice had to be adopted of ending observations on these lines only when the results on at least two nights showed a satisfactory agreement. Lateral refraction affecting the observations by from 5 seconds to 15 seconds of are was not at all uncommon, and it has been estimated that almost three times the amount of clear weather ordinarily necessary to secure the required program of observations was used to secure the required accuracy. Even with the precautions which were taken, the evidence shows a regular bending towards the river of the lines parallel to the river. This is evidenced by the error of closure of triangles, the sum of the three observed angles being less than the theoretical sum in the majority of cases.

Isostasie und Schweremessung: Bedeutung für geologische Vorgänge

THE variation from place to place of the intensity and direction of the force of gravitation is one of the comparatively few phenomena from which we can obtain some knowledge of the nature of the earth's interior. We owe to Pratt and Airy the demonstration in 1855 that, broadly speaking, different regions of the earth's crust balance one another, or, as it is now expressed, are in a state of isostasy; that the weight of mountain masses above the sea-level is compensated by a defect of density below them, and that ocean deeps are underlain by material of high density. But, whereas Pratt believed that the high places of the earth were the result of expansion of the material beneath them, Airy compared a mountain range to a log of wood floating in water, which it displaced and by which it was buoyed up. After nearly seventy years the same difference of opinion as to the real meaning of isostasy continues to persist. Isostasie und Schweremessung: ihre Bedeutung fur geologische Vorgange. Von Prof. Dr. A. Born. Pp. iii + 160. (Berlin: Julius Springer, 1923.) 2.20 dollars.

I.—On the Origin of some Land-forms in Caernarvonshire, North Wales

The present paper deals with some 30 square miles of land situated in Caernarvonshire and embracing the drainage area of the River Ogwen and parts of adjacent river-basins. It is doubtful if any part of Great Britain presents in such a small area so many interesting topographical features and such beautiful and diversified scenery as this part of North Wales. It is in part a thoroughly mountainous region accompanied by characteristics that belong to mountains, and it is a glaciated mountain region with typical glacial topography. But adjoining the mountains is an area of entirely different characteristics, and the change from the one to the other is sudden and complete. An upland plain abruptly terminates against a range of mountains without the interposition of foot-hills, the crags and pinnacles rising precipitously from the level land; or, in other words, the plain cuts as it were a shelf in the mountainous masses.

GUNNERA PETALOIDEA GAUD., A REMARKABLE PLANT OF THE HAWAIIAN ISLANDS

A distinctive feature of the Hawaiian flora is the prevailing endemicity of the rain-forest species. About 85 percent of the flowering plants of the islands are endemic, and the bulk of these are characteristic of the rain-forest zone. This zone lies between the elevations of 2,000-6,000 ft. The mountains of Kauai, Oahu, East Molokai, West Maui, and the Kohala Range on Hawaii, rise to heights of 3,0006,ooo ft., and thus their summits are covered with dense rain-forest vegetation. The great valleys of erosion have eaten back into the very hearts of these mountain masses, so that the summit regions abound in knife-edged ridges and great precipices. Many of the summit ridges are only three or four feet wide at the crest; many of the precipices are 8oo-i,8oo ft. high. The rainfall in these regions is torrential, and much of the vegetation is of the most pronounced hygrophytic type. One of the most characteristic and conspicuous plants of these humid summit regions is the endemic halorrhagaceous Gunnera petaloidea Gaud.' In the little hanging valleys that abound in this zone, on the precipices as well as in the steep stream-beds, are masses of this titanic herbaceous-perennial. The gigantic leaf-blades are three to four feet in diameter, peltate on fleshy petioles two or more feet long.2 The petioles arise from a creeping or erect rhizome, which is fleshy, green, and four or five inches in diameter. The huge crown of leaves springs from the apex of the rhizome. As the latter is often branched, the total mass of foliage was spread over an area of ten or twenty square feet, with a height of six or eight feet. In places where they have not been disturbed by the landslides that are common in these regions, these gigantic herbs often cover areas fifty to a hundred feet long and twenty or more feet wide, as on the upper slopes of a precipice, where they form a beautiful mural tapestry.

The Tertiary Volcanic Rocks of the District of Mozambique

Introduction. I. History Of Exploration The Portuguese East-African District of Mozambique was, until recently, one of the least known of the East-African coastlands. Livingstone explored the regions on the south-west (1865) and north (1874), but Mozambique itself he did not touch. Sadebeck (1879) was the first to give a geological description of the sedimentary rocks that fringe the coastal plain of the mainland north and south of Mozambique Island. This work was followed up by Choffat (1903) in an important palæontological memoir on the Cretaceous formations of Conducia Bay. Exploration beyond the coastal zone was initiated by Lieut. H. E. O'Neill, who made a number of successful journeys westwards across the mainland during the years 1881–1884. In his papers (1882, 1884, 1885) he gives a very complete and faithful account of the natives and their customs; but, beyond the suggestion that the prevailing rocks are gneisses and granites, he makes no reference to the geology of the territory. In 1887, Mr. J. T. Last made a journey from Blantyre to the Namuli Peaks, which had for long been considered to be of volcanic origin. This view he disproved (Last, 1887), describing the summit as ‘an almost perpendicular mass of white stone.’ I have since learned from Mr. Last that he referred in this expression to the grey granite and gneiss which builds up the Namuli Peaks, as it does the other mountainous masses of the country. Thus, until a few years ago, Mozambique, with the exception of part of the

I.—The Lateritic Deposits of Mozambique

In his Last Journals, referring to the formations of Portuguese Nyasaland west of the Lugenda River, Livingstone writes: “The elevated plains among these mountain masses show great patches of ferruginous conglomerate, which, when broken, looks like yellow hæmatite with madrepore holes in it.” He also notes that the same formation is responsible for the prevailing reddish tint assumed by the soil. In Mozambique, the province of Portuguese East Africa south of Nyasaland, lateritic deposits of the kind described by Living-stone are very abundant. In view of the wide interest which the superficial deposits known as laterite have aroused among geologists during recent years, no excuse seems necessary for placing on record a few notes dealing with their modes of occurrence and associations in Mozambique. The country was explored during the year 1911, Mr. D. A. Wray, Mr. E. J. Wayland, and myself accompanying the expedition as geologists. My former colleagues have kindly placed their notes on the superficial deposits of Mozambique at my disposal, and I wish here to express my indebtedness to them for the help thus afforded.

Rock-Cut Surfaces in the Desert Ranges

In an article entitled Geographical Cycle in an Arid Climate 2 William M. Davis has presented a physiographic analysis of the ultimate results of erosion in an arid region. His conclusions are based partly on the work of Passarge and others and partly upon his own deductions. The system erected is in its larger features so complete those who follow in interpreting particular physiographic products need only assign such features to their proper place in the larger system already established. That the following conclusions, therefore, were reached independently and seem to fit perfectly with the system outlined by Davis is an additional corroboration of the soundness of his deductions, and the excuse for their publication must rest upon the wish expressed by Davis that the scheme of the arid cycle may lead to the detection of many facts concerning the evolution of land forms in desert regions have thus far escaped notice. G. K. Gilbert3 stated in describing the Basin Range system of the West: Between them [the ranges] are valleys floored by the detritus from the mountains which conceals their depth and leaves to the imagination to picture the full proportions of ranges of which the crests alone are visible, while the bases are buried beneath the debris from the summits. It is with the processes by which gravel sheets engulf mountain masses and with certain erosional features associated with such accumulations the

II.—Notes on the Structure and Physiography of the Tarntal Mass

The mountain mass known as the Tarntaler Köpfe, situated about 20 kilometres south-east of Innsbruck, is distinctly isolated from other high ground in the vicinity. The peaks rise to heights approaching 2900 metres above sea-level. The geologic features above the level of 2000 metres are of special interest. The adjacent country is occupied by crystalline phyllites, chiefly displayed on the north, and highly foliated calcareous schists developed mostly on the south of the mountain.

The occurrence of volcanic tuffs on Ben Nevis

In the summer of 1904, while on Ben Nevis, I collected two specimens of what at the time were believed to represent:— (1) A typical specimen of the andesite of that mountain, (2) a brecciated form of the same rock. On examining these in micro-section over a year afterwards, I was surprised to find that the first, which was supposed to be a typical example of the andesite, showed the fine brecciation and injection of one andesite by a second andesite, while the other was found to be a typical volcanic tuff. Brecciation on a large scale of the andesite of Ben Nevis has been described by Nicol, and at a later date by Judd; but there is no record, so far as known to me, of finer fragmental volcanic rocks occurring on that mountain, and certainly none of the occurrence of tuffs. The first specimen was collected from the right side of the footpath as one ascends, at a point just where it reaches the level of the plateau on which the lake is situated, and from what is probably the very first outcrop of andesite encountered in the ascent. Between the lake and the mountain mass to the east, many of the loose blocks which have fallen from the cliffs or have weathered out of the rocky platform show a rough nodular aspect on a weathered surface, and break with a brecciated, hackly fracture under the hammer. The second specimen was collected from the centre of one of

Interdependent evolution of oases and civilizations

Physical Development of central Asia The beginnings of central Asia, as part of the Great continent, lie far back in the Tertiary period, during a time when mother Earth was in travail, giving birth to her last-born, the new order of continental and organic forms. In the throes of the contracting terrestrial crust there had been slowly born great mountain masses, ranges whose ice-capped giants now mark the boundary between north and south, extending half way round the earth, through the Pyrenees, Caucasus, and Himalayas to China. The Eurasian continent was born, but in its infancy a great sea extended from the Atlantic through the Mediterranean to southeastern Asia. Later, during the middle Tertiary, this connection was broken, leaving a great interior sea called the Sarmatic, which once extended from Austria to beyond the Aral. In the progressive development of land and climate, during Pliocene or late Tertiary time, this . . .

IV.—The Circular form of Mountain Chains

I am a stranger in the field of speculation, and am quite unacquainted with the intricacies of its authorized boundaries. It is therefore with some hesitation, lest I should tread upon forbidden ground, that I venture to offer a suggestion on one point in Professor Sollas's paper on “The Figure of the Earth.”It has long been observed that mountain ranges and chains of islands (which, indeed, are only mountain ranges partially submerged) are generally curvilinear in form, but Professor Sollas is, I believe, the first to show clearly that the curve often coincides almost exactly with an arc of a circle. Such a mountain chain is frequently defined along its convex margin by a great reversed fault over which the mountain mass has slid forward; and in these cases, at least, we may safely adopt Suess's conception, and look upon the chain as the crumpled edge of a ‘scale’ of the earth's crust which has been pushed forward over the part in front of it. The surface along which the movement has taken place is called a thrustplane. If this surface really is a plane, then the edge of the ‘scale’, that is the mountain chain itself, must necessarily be circular in form; for if any plane cuts a sphere, in any position whatever, the outcrop of the plane on the surface of the sphere will always be a circle. There can be no deviation from the circular form unless the ‘sphere’ is not truly spherical, or the ‘thrust-plane’ is not a true plane.

Notes on the Geology of Mount Kearsarge, New Hampshire

Previous articleNext article FreeNotes on the Geology of Mount Kearsarge, New HampshireJoseph H. PerryJoseph H. Perry Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Journal of Geology Volume 11, Number 4May - Jun., 1903 Article DOIhttps://doi.org/10.1086/621085 Views: 83Total views on this site PDF download Crossref reports no articles citing this article.

Mountain Masses and Latitude Determinations 1

Mountain Masses and Latitude Determinations 1

Die hochgebirge der Erde

THIS is a most conscientious piece of bookmaking. The author appears to have read and made a summary of all the more important descriptions of the mountain masses of the globe. Beginning with a sketch of the physiography of mountains, their development and sculpturing, he passes on to describe them chain by chain. As he has himself travelled much, he can often speak from personal experience, while the numerous and generally excellent illustrations enable the reader to realise the different types of scenery. Reproductions of photographs are used in most cases, but occasionally, of course, copies of engravings, variable in quality, were alone available. Some, both of the one and the other, have done duty before, and a few perhaps may be more attractive to the general than to the scientific public. Pictures, for instance, of climbers in a mist seem more appropriate to a book of travels, and some of those representing mountain plants or animals are hardly such as to enhance the value of the book. Attractive also as are all Mr. E. T. Compton's sketches, we cannot but feel that in a treatise of this kind reproductions of photographs would have been better, for accurate delineation is sometimes sacrificed to artistic sensibility. This is especially true of the drawing of the Grivola on p. 128. in which we have not found it easy to make out the topography. These, however, are matters of opinion. The book contains a vast mass of information, brought down to the latest possible date, and collected with a thoroughness and accuracy truly German. Die hochgebirge der Erde. Von Robert von Lendenfeld. Mit titelbild in Farbendruck 148 Abbildungen und 15 Karten. Pp. xiv + 532. (Freiburg im Breisgau: Herdersche Verlagshandlung, 1899.)

The Volcanic Condition of Stromboli

IN view of the fact that all published accounts of Stromboli, according to the resume given by Bergeat (“Der Stromboli,” A. Bergeat, Habilitationschrift, Munchen, 1896), have agreed in describing the volcano as being explosively active, there may some interest attach to a statement of the present condition of affairs, as seen by Prof. H. F. Reid, of Johns Hopkins University, and the writer, on October 27 and 28 of the present year. The westernmost of the four small craters described by Bergeat was not observed at all, the next two were discharging rather copious volumes of vapour, and the easternmost, or “old,” crater was giving out a very little steam from its bottom. The most steam was issuing from cracks in the eastern rim of the “old” crater, especially from one at the north-eastern or seaward corner of the rim. Much steam was issuing from the southern rim overhanging the second and third craters, and the ridge leading from it to the main mountain mass. Nothing in the nature of an eruption was taking place, and it was evident that the craters had been in this condition for some time. Later inquiry at Lipari elicited the information from Bartolo Nicotera, the guide, that there had been no eruption on Stromboli for about a year. The high ridge over the crater, known as the Cima, showed steam issuing from along its summit, more than 200 metres above the crater.

THE HOPI IN RELATION TO THEIR PLANT ENVIRONMENT

The country of the Hopi, in northeastern Arizona, is arid and semi-desert. From the last stronghold of this p)eople on the precipitous boat-shape mesas of the high plateau, offshoots of the mountain knots of the Carrizos, one sees only barrenness, but barrenness painted beyond description. TI'o the south the strange, fantastic outline of lava-capped buttes; to the west, beyond the plain, the faint line of the Mogollones, 110 miles away, flanked by the mighty mountain mass of the San Francisco, and to the north and east mesa after mesa fading into the horizon. A nearer view of the plain reveals a waste of sand, sparsely dotted with the characteristic vegetation of the arid region and cut by gullies and washes, which rarely by the good will of the rain-gods give a glint of water. A few cottonwoods among the cornfields in the beds of the washes delight the eye by their dark green foliage, amid so much desolation,while on the distant mesas scattered cedars have a foothold.