Intertidal zone

“ The breadth of the frontier zone is indicative of the activity of growth on the one side and the corresponding decline on the other, because extensive encroachment in the same degree disintegrates the territory of the neighbor at whose cost such encroachment is made. A straight, narrow race boundary, especially if it is nearly coincident with a political boundary, points to an equilibrium of forces which means, for the time being at least, a cessation of growth. ”

“ Twice in the twenty-four hours the littoral zone is covered by water and exposed to the direct rays of the sun or the cooling effects of the night. There is a great range of temperature; mechanical agencies produce their maximum effects,” [171] and physical conditions in general are most varied. Still greater diversity is introduced by the fact that the zone is inhabited by both marine and terrestrial organisms, while the evaporation of the sea-water which flows over tidal marshes and lagoons leads to the formation of saline deposits. ”

“ Despite its isthmian character, the Canal Zone, Uncle Sam’s most southerly outpost, may be called an island, for the travelers’ purpose. True it is bordered on but two sides by water, and thus far violates the definition of an island. But it is only to be reached by water. The other two sides are walled in by the tangled jungle where vegetation grows so rank and lush that animal life is stunted and beaten in the struggle for existence by the towering palms, clustering ferns and creeping vines. ”

“ The Canal Zone is a strip of land ten miles wide running across the Isthmus—really an American colony, you know, for we govern it, police it, and all that. As for the work itself, well, the fellows at the two ends of the Canal are dredging night and day to complete their part, the lock-builders are laying concrete like mad to get their share done first, the chaps in the big cut are boring through the hills like moles and breaking steam-shovel records every week, while we railroad men take care of the whole shooting-match. ”

“ The earth is divided in purely formal fashion into five zones, two of which are habitable: our temperate zone and the unknown temperate zone of the antipodes (in the southern hemisphere) ; and three uninhabitable: the torrid zone with the equatorial ocean, and the two frigid zones, north and south. These conceptions also reached the North at an early time, and are mentioned in the “King’s Mirror,” amongst other works, although its author thought that the inhabited part of Greenland really lay in the frigid zone. A zone-map from Iceland is also known of the thirteenth century. ”

“ These two zones are connected by a vertical strip of grassy highland lying mainly to the east of the chain of great lakes. The third zone is a vast region of forest and rivers in the west centre, comprising the greater part of the basin of the Congo and the Guinea coast. The rainfall, which also has an important bearing upon the culture of peoples, will be found on the whole to be greatest in the third zone and also in the eastern highlands, and of course least in the desert, the steppes and savannas standing midway between the two. ”

“ So loose are ties down on the Zone that a man's room-mate might go off into the jungle and die and the former not dream of inquiring for him for a week. Especially we world-wanderers, as are a large percentage of "Zoners," with virtually no fixed roots in any soil, floating wherever the job suggests or the spirit moves, have the facts of our past in our own heads only. ”

“ The Canal Zone is an outpost of a high civilization in the tropics. It affords object lessons to the neighboring republics of Central America in architecture, sanitation, road building, education, civil government and indeed all the practical arts that go to make a State comfortable and prosperous. ”

“ I scribbled myself a ticket and was soon rolling northward, greeting acquaintances at every station. The Zone is like Egypt; whoever moves must travel by the same route. At Pedro Miguel and Cascadas armies of locomotives—the "mules" of the man from Arkansas—stood steaming and panting in the twilight after their day's labor and the wild race homeward under hungry engineers. ”

“ These vegetation zones should not be visualized as nice neat bands on the mountainsides, however, for roughness of topography and differing tolerances of plant species usually lead to gradual changes from one zone to the next. Because of the greater exposure to drying heat and sunlight, each belt occupies a higher range of elevation on south-facing slopes than on north-facing ones. ”

“ Even civilized peoples may adopt a waste boundary where the motive for protection is peculiarly strong, as in the half-mile neutral zone of lowland which ties the rock of Gibraltar to Spain. On a sparsely populated frontier, where the abundance of land reduces its value, they may throw the boundary into the form of a common district, as in the vast, disputed Oregon country, accepted provisionally as a district of joint occupancy between the United States and Canada from 1818 to 1846, or that wide highland border which Norway so long shared with Russia and Sweden. ”

“ As changes must be gradual in every direction, care must be taken to make the contiguous zones blend into each other. When it is required to pass from a light zone to a darker one beneath it, the lower ends of the lines in the light zone should be thickened a little, so as to meet the upper ends of the lines in the dark zone with nearly the same colour. ”

“ There, in British Columbia, reproductive isolation is not complete and occasional populations of intergrades occur. In Montana extensive intergradation occurs in a broad zone of transitional habitat. Along the western edge of the Rockies from Idaho south to Utah the zone of transition from montane to basin habitat is sharp and the zone of intergradation, although present, is fairly narrow, perhaps because there is little intermediate habitat which logically might be expected to be most suitable for intergrading populations. ”

“ The normal unit of food and labour in a zone is to be determined by the normal, that is, average-sized farm-household in one of the districts (or any other administrative and farming unit, equal in size) of the zone, having a density of population which is the lowest in the zone, and such a proportion of various kinds of lands (arable, pasture, alluvial, dried-up, meadow, waste, kitchen-garden, etc.) ”

“ There is not so much land in the world that this need be wasted, nor have there been so many examples of the successful creation and continuance of such a community as the Zone has been as to justify its obliteration before the world has grasped its greatest significance. ”

“ The preservation of such surfaces after a second ice invasion must be regarded as the exception rather than as the rule. There is always the possibility, too, that an oxidized and weathered zone marking the surface of an older drift sheet exists, where excavations have not opened full sections of drift to view. The absence of weathered zones of drift beneath the surface, or the absence of knowledge of their existence, is therefore at best no more than negative evidence. ”

“ Between these two lines is an area about sixteen miles wide where these zones overlap, which the author calls the "tension zone," because a constant state of strain or tension in the struggle for existence prevails in it. In the deciduous zone the geological formations are numerous, with various soils and every gradation of topography, and the diversity of trees is great. ”

“ On the outer zone are extensive residential areas, then a zone of factories and workshops, and beyond that an area often extending for miles, which is covered with cereals and vegetables, fruit trees and nut trees. Outside all is a zone of timber trees. The town and its surroundings, therefore, cover a vast area.
The canals radiate in all directions from the outer edge of the wide ring-canal, and all quays, wharves, and warehouses are alongside of these canals. ”

“ Next to this zone, we can in the same way find the limits of others presiding over other movements. The influence appears greatest at the center of the zone: exciting the periphery sometimes produces a light supplementary movement belonging to a neighboring zone. The special centers or zones being very near together, our means of electrizing them are not perfect enough to prevent a slight diffusion of the current into neighboring centers and faintly exciting them. To get precise separate effects we must excite the center of the special zone. ”

“ The area above this point is known as the vadose zone, and below this point the area is the ground-water or phreatic zone.
Any farmer who has ever sunk a well knows how important it is that his well reach below the water table if he is to be assured a continuous supply of water. Well owners also know that the water table can rise or fall due to any of several natural causes, such as an abundance of rainfall for a few seasons, or any great lack of rainfall for an extended length of time. ”

“ The confines of all these regions cross and merge into one another, at times, on account of the altitude in their different zones. The vegetation typical of one zone is often scattered through one or more neighbouring ones, so that they cannot be exactly defined. The greater or lesser altitude of a place often goes towards modifying the uniform character of the vegetation. ”

“ The second zone consists chiefly of Cretaceous and early Tertiary rocks. In the west it is broad, including the whole of the Greater Antilles, but in the east it is restricted to a narrow belt which comprises the Virgin Islands (except Anegada) , Anguilla, St Bartholomew, Antigua, the eastern part of Guadeloupe and part of Barbados. (3) The third and outermost zone is formed of Miocene and later beds, and the islands which compose it are flat and low. Like the second zone it is broad in the west and narrow in the east. It includes the Bahamas, Anegada, Sombrero, Barbuda and part of Barbados. ”

“ The Exclusive Economic Zone extends to a distance 200 nautical miles from the baseline from which the breadth of the territorial sea is measured. In eases where the maritime boundary with a neighboring State remains to be determined, the boundary of the Exclusive Economic Zone shall be determined by the United States and other State concerned in accordance with equitable principles. ”

“ Thus every part of the middle zone has been successively the frontier between the northern and southern groups, and consequently their remains are mingled together in the caverns and river deposits, under conditions which prove them to have been contemporaries in the same region. ”

“ The contiguous zone of the United States is a zone contiguous to the territorial sea of the United States, in which the United States may exercise the control necessary to prevent infringement of its customs, fiscal, immigration, or sanitary laws and regulations within its territory or territorial sea, and to punish infringement of the above laws and regulations committed within its territory or territorial sea. ”

“ One great physical barrier would, however, even then exist; the hot equatorial zone would divide the faunas and floras of the colder regions of the northern and southern hemispheres from any chance of intermixture. ”

“ First, the arctic province, with prevailing uniformity. Second, the temperate zone, with at least three distinct zoological provinces—the European temperate zone, west of the Ural Mountains, the Asiatic temperate [Pg 24] zone east of the Ural Mountains, and the American temperate zone, which may be subdivided into two, the eastern and the western—for the animals east and west of the Rocky Mountains differ sufficiently to constitute two distinct zoological provinces. ”

“ Thus both the physical and biological conditions of the zone farther inland affect the beach flora quite as distinctly as do the conditions shoreward." The line between mid-strand and back-strand may be called a tension line, as between two general groups of plants striving to move in opposite directions, where a reciprocal stress is developed; and the plants of the mid-strand strive to enter the back strand, while the others try in turn to work out upon the mid-strand. ”

“ VII and VIII, the zone-observations made in 1875. In making these observations, between declinations 23° and 47°, the normal width of the zone was two degrees, with 10' additional at each margin and extremity for overlap; from 47° to 75°, their width increased with the declination; until, finally, the last five degrees, 75° to 80°, were comprised in a single belt. The zones were also subdivided, where that seemed best.
The Distribution of Products, or the Mechanism and Metaphysics oe Exchange. By Edward Atkinson. New York: G. P. Putnam's Sons. Pp. 303. Price, $1.25. ”

“ The zone of melancholy which I then entered was totally distinct from that other zone, in which I had been bounding for joy a moment earlier, just as sometimes in the sky a band of pink is separated, as though by a line invisibly ruled, from a band of green or black. You may see a bird flying across the pink; it draws near the border-line, touches it, enters and is lost upon the black. ”

“ The piedmont boundary also divides two areas of contrasted density of population. Mountain regions are, as a rule, more sparsely settled than plains. The piedmont is normally a transition region in this respect; but where high mountains rise as climatic islands of adequate water supply out of desert and steppes, they concentrate on their lower slopes all the sedentary population, making their piedmonts zones of greatest density. Low mountains in arid regions become centers of population; here their barrier nature vanishes. ”