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THE EDINBURGH JOURNAL OF NATURAL HISTORY. 



which lie scattered on tha sides and summits of the chains of hills through which it 

 has found a passage ; that much of the water-worn gravel, which has been drifted 

 throuo-h the breaches op^nied in the sinuous line of its channel, is composed of rocks 

 not found within the limits of its basin ; and that the form of the country is often the 

 very reverse of that which would have been produced by mere fluviitile erosion, 

 however long continued. Similar facts are supplied by nearly all the greater valleys 

 of Eno-land; and on the whole, they point to one conclusion, that the fluviatile ero- 

 sion, as a mere solitary agent, has produced but small effects in modifying the pro- 

 minent features of our island : at the same time, they leave untouched a'.l the facts of 

 an opposito kind supported by direct evidence, whether derived from the volcanic 

 districts of Central France, or from any other physical region on the surface of the 

 earth. 



The power of mountain torrents in transporting heavy masses of stone is strikingly 

 illustrated in a paper by Mr CuUey. He states that a small rivulet descending from 

 the Cheviot Hills along a moderate decllnty, carried down, during a single flood, 

 many thousand tons of gravel into the plains below; and that several blocks, from 

 one-half to three quarters of a ton weight each, were propelled two miles in the di- 

 rection of the stream. Facts similar in kind, but on a scale incomparably greater, 

 must be in the recollection of every one who has seen the Alpine torrents descending 

 into the plains of the north of Italy. 



When mountain chains abut in the sea, the laws of degradation are not suspended. 

 At each successive flood, fragments of rock are drifted in the direction of the de- 

 scending torrents, and rolled beneath the waters. This kind of action is indeed 

 casual and interrupted; but it is aided by another action which is liable to no inter- 

 mission — the beating of the surf and the grinding of the tidal currents on all the 

 projecting parts of a steep and rocky shore. Under such conditions there are now 

 forming at the bottom of the sea, and at depths perhaps inaccessible, alternating 

 masses of silt and sand, and gravel, which, if ever lifted above the waters, may rival 

 in magnitude some of the congiomorates of our oldest formations. 



Professor Sedgwick is of opinion, that the existing drainage of our physical re- 

 gion is a complex result, depending upon many conditions — the time when the region 

 first became dry land — its external form at the time of its first elevation above the 



sea and all the successive disturbing forces which have since acted upon its surface. 



But none of these elements are constant ; no wonder, then, that results derived from 

 distant parts of the earth should be so greatly in conflict with each, other. In the 

 formation of valleys there is, therefore, little wisdom in attributing every thing to 

 the action of one modifying cause. We know by direct geological evidence, that 

 nearly all the solid portions of the earth were once under the sea, and were lifted to 

 their present elevation, not at one time, but during many distinct periods. This is 

 proved beyond a doubt, by the various marine shells which are found in the strata of 

 the different formations, all of them having existed in the ocean at different epochs 

 of time, and varying in their structure according to the various eras when they ex- 

 isted ; the most simply organized being buried in the most ancient beds, and the 

 most complicated in the most recent. We know that elevating forces have not 

 only acted in different places at different times, but with such variations of intensity, 

 tliat- the same formation is in one country horizontal, in another vertical ; in »one 

 country occupies the plains, in another is only found at the tops of the highest moun- 

 tams. "Now every great irregular elevation of the land (independently of all other 

 results) must have produced, not merely a rush of the retiring waters of the sea, 

 but a destruction of equilibrium among the waters of inland drainage. Effects like 

 thosi'- must have been followed by changes, in the channels of rivers, by the bursting 

 of lakes, by great debacles, and, in short, by all the vast phenomena of denudation. 

 In comDarincr distant parts of the earth, we may therefore affirm that the periods of 

 denudation do not belong to one, but to many successive epochs. And by parity of 

 reasonino- we may conclude, that the great masses of incoherent matter which lie scat- 

 tered over so many parts of the surface of the earth, belong also to successive epochs, 

 and partake of the same complexity of formation. 



The excavation of valleys seems, therefore, to be a complex result, depending upon 

 all the forces, which, acting on the surface of the earth since it rose above the waters, 

 have fashioned it into its present form. We have old oceanic valleys which were 

 formed at the bottom of the sea in times anterior to the elevation of our continents. 

 Such is the great valley of the Caledonian Canal, which existed nearly in its present 

 form at a period anterior to the congiomorates of the old red sandstone. We have 

 longitudinal valleys formed along the line of jimction of two contiguous formations, 

 simply by the elevation of their beds. To this class belong some of the great longi- 

 tudinal valleys of the Alps. We have other valleys of rnoi-e complex origin, where 

 the beds through which the waters now pass have been bent and fractured with an 

 inverted dip at the period of their elevation. Such is the valley of Kingsclere de- 

 scribed by Dr Buckland. We have valleys of disruption, marking the direction of 

 cracks and fissures, produced by great upheaving forces. Such are some of the 

 great transverse valleys of the Alps. Of valleys of denudation, our island offers a 

 countless number. Some are of simple origin ; for example, the dry valleys of the 

 chalk formation, which appear to be swept out by one flood of retiring waters during 

 some period of elevation. Others are of complex origin, and are referable to many 

 periods, and to several independent causes. Lastly, we have valleys of simple 

 erosion : such are some of the deep gorges and river channels in the high regions 

 of Auvergne, excavated solely by the long continued attritions of the rivers which 

 still flow through them. 



South Aimerican Geology. — M. Orbigny, who explored the countries of 

 Buenos Ayres, Chili, and Peru, mentions some remarkable facts respecting fossil 

 remains being found in those countries at a great height. He found primitive for- 

 mations in the greater part of Brazil and of the Bande Oriental. The immense basin, 

 which extends from the 25th to the 38th degree of south latitude, was the first place 

 where he detected animal remains in strata, which he reckoned of the tertiai-y forma- 

 tion. The vegetable remains were below the bones of the IMammiferous animals, 

 which were, in their turn, covered by banks of river shells. The sides of the rivers 

 are high, presenting every facihty for observing these superpositions. To the south 

 a primitive chain of mountains separated this geological basin from that of Patagonia. 



This last is analogous in a certain degree to the basin of Paris, in presenting alternat- 

 ing strata of oysters and freestone with osseous remains, gypsum, and river shells 

 ■M. Orbigny is decidedly of opinion that the higher plains of the Andes are volcanic* 

 at the height of 12,000 ieet he discovered marine fossils. 



GENERAL SCIENCE. 



TUAKSFOUJIATION OP VEGETABLE SUBSTANCES INTO A NeW PRINCIPLE.—' 



Bracconot has discovered that vegetaT)le substances produce, when heated with con 

 centrated nitric acid, compounds very different from those afforded when diluted nitric 

 acid is used. Saw-dust, cotton, linen, fecula from the potatoe gum, issoline and 

 soponine, heated with concentrated nitric acid, arc transformed into a peculiar muci- 

 laginous substance, called by Bracconot Xiloidine. It is transparent, and is red- 

 dened by turnsole; cold water coagulates it, and boiling water softens without dis- 

 solving it. It is insoluble in alcohol and ammonia ; and caustic potash dissolves it 

 with great difficulty. On the other hand, the acids dissolve it in great quantities 

 without altering it ; the solutions leave upon bodies a brilliant varnish. 



Prospects of the Negro Population in South Asierica, and of the 



Gradual Extinction of the Original Inhabitants of the New World. 



Dr Poeppig, in his account of Chili, has the following important observations on 

 these interesting subjects: — *' No country in America enjoys, to such a degree as 

 Chih, the advantages which a state derives from an homogeneous population and the 

 absence of Castes. If this young republic rose more speedily than any of the others, 

 from the anai'chy of the revolutionary struggle, and has attained a high degree of 

 civiUzation and order, with a rapidity of which there is no other example in this con- 

 tinent, it is chiefly indebted for these advantages to the circumstance, that there are 

 extremely few people of colour among its citizens. Those various transitions of one 

 race into the other are here unknown, which strangers find it so difficult to distin- 

 guish, and which, in countries like Brazil, must lead, sooner or later, to a dreadful 

 war of extermination, and in Peru and Columbia, will defer to a period indefinitely 

 remote, the establishment of general civilization. * * * If it is a great evil for 

 a state to have two very different races of men for its citizens, the disorder becomes 

 general, and the most dangerous collisions ensue, when, by an unavoidable mixture, 

 races arise which belong to neither party, and in general inherit all the vices of their 

 parents, but very rarely any of their virtues. If the population of Peru consisted of 

 only whites and Indians, the situation of the country would be less hopeless than it 

 must now appear to every cahn observer. Destined as they seem by nature herself, 

 to exist on the earth as a race, for a limited period only, the Indians, both in the 

 north and south of this vast continent, in spite of all the measures which humanity 

 dictates, are becoming extinct with equal rapidity, and in a few centuries will leave 

 to the whites the undisputed possession of the country. With the Neoroes the case 

 is different ; they have found in America a country which is even more congenial to 

 their nature than the land of their origin, so that their numbers are almost every where 

 increasing in a manner calculated to excite the most serious alarm. In the same propor- 

 tion as they multiply, and the white population is no longer recruited by frequent sup- 

 pUes from the Spanish Peninsula, the people of colour likewise become more numer- 

 ous. Hated by the dark mother, distrusted by the white father, they look on the 

 former with contempt, on the latter with aversion, which circumstances only suppress 

 but which is insuperable, as it is founded on a high degree of innate pride. All 

 measures suggested by experience and policy, if not to amalgamate the heteroo-eneous 

 elements of the population, yet to order them so that they might subsist together 

 without collision, and contribute in common to the preservation of the machine of 

 the State, have proved fruitless * * * *_ T^e late revolutions have made no 

 change in this respect. The hostility, the hatred of the many coloured classes will 

 continue a constant check to the advancement of the State, full of danger to the in- 

 dividual citizens, and perhaps the ground of the extinction of entire nations. The 

 fate which must, sooner or later, befal the great part of tropical America which is 

 filled with Negro Slaves, which will deluge the fairest provinces of Brazil with blood 

 and convert them into a desert, where the civilized white man will never again be 

 able to establish himself, may not indeed afBict Peru and Columbia to the same ex- 

 tent, but these countries will always suffer from the evils resulting from the presence 

 of an alien race. If such a country as the United States feels itself checked and 

 impeded by its proportionably less predominant black population; and if there where 

 the wisdom and power of the government are supported by public spirit, remedial 

 measures arc sought in vain; how much greater must be the evil in countries like 

 Peru, where the supine character of the whites favours incessant revolution, where 

 the temporary rulers are not distinguished either for prudence or real patriotism ■ and 

 the infinitely rude Negro possesses only brutal strength, which makes him doubly 

 dangerous in such countries, where morality is at so low an ebb. He and his half 

 descendant, the Mulatto, joined the White Peruvian to expel the Spaniards, but 

 would soon turn against their former allies, were they not at present kept back by 

 want of moral energy and education. But the Negro and the man of colour, far 

 more energetic than the White Creole, will in time acquire knowledge, and a way of 

 thinking that will place them on a level with the Whites, who do not advance in the 

 same proportion so as to maintain superiority." 



Education — How greatly is Nature neglected in all our Schools! " Ten years," 

 says Erasmus, "have I wasted in reading Cicero." Decern nnnos consumpsi in le- 

 gendo CiccrovE. The Echo replied in Greek, "Oy£ (Ass!) 



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