S92 



MINERALOGY. 



Geognosy, tain and the ravine to the great fabric of the high coun- 

 S """V" 1 ^ try ; and still further to the most general division of 



the inequalities of the earth's surface, the dry land and 



the bottom of the sea. 



First Degree. 

 Dry Land. Bottom of the Sea. 



Second Degree. 

 High Land. Low Land. 



Third Degree. 

 Alpine Land. Plain. 



The mountainous and hilly land make the transition 

 from the Alpine land to the plain. 



Fourth Degree. 

 Mountain Range. Valley. 



Fifth Degree. 

 Mountain. Ravine. 



We shall now consider each of these inequalities in 

 detail. 



6. In regard to the bottom of the sea, we may at pre- 

 sent remark, that it is diversified by many inequalities; 

 which, however, are not so special as those on the sur- 

 face of the dry land. 



The ocean covers about three-fifths of the whole 

 earth, so that there is but a comparatively small por- 

 tion of it elevated above the surface of the water. Even 

 this does not form a connected whole; on the con- 

 trary, it is divided into a number of detached masses, 

 to which geographers have given different names : 

 the larger are denominated continents, the smaller, 

 islands. 



The geographic division of the earth into continents 

 is not quite correct. Thus Europe and Asia, which 

 form but one continent, are by geographers divided 

 into two; whereas America, which forms two very 

 distinct continents, having their natural boundary at 

 the Isthmus of Darien, is considered as one. Europe 



Division of 

 the earth 

 into conti- 

 nents. 





and Asia should therefore be considered as forming one Geognosy* 

 continent, and America two. Africa, on the contrary, > ^V~' 

 is well characterised as a distinct continent. 



The great inequality of the distribution of the land, 

 which rises above the surface of the ocean, deserves at 

 tention. If we conceive the earth divided into two 

 equal parts by the equator, we shall find a most strik- 

 ing difference in the proportion of land on its north 

 and south sides : the southern half is almost entirely 

 composed of water ; but in the northern, the greater 

 portion is land. The proportion of land on the north 

 and south sides of the equator, is as jS to J. It has 

 been also observed, that if the earth be divided by a 

 meridian line, the proportion of land and water on op- 

 posite sides is strikingly different ; there being always 

 a preponderance of water in the one side, and land on 

 the other. 



This great accumulation of land in the northern half 

 of the globe, suggested to some speculators the idea of 

 the existence of a southern continent ; as they conceiv- 

 ed it to be impossible that the equipoise of the earth 

 could otherwise remain undisturbed. The illustrious 

 Cook, however, has shewn, that even beyond 71 S. 

 latitude, there is no appearance of a continent ; and 

 that these dreary regions of water and ice are only di- 

 versified by a few islands *. 



7. The most .general inequalities observable on the High land, 

 surface of the dry land, are, as we have already ob- 

 served, high land and low land. By the first, we un- 

 derstand a lofty, uneven, and widely extended mass of 

 land : by the second, a great and widely extended low 

 and flat country. 



In Europe, we find but two high lands and one low 

 land. The one is the great European or Southern; 

 the other the Scandinavian or Northern. The one has 

 its middle point in Switzerland, in the Tyrol, and the 

 Alps of Savoy. Hence it passes through three-fourths 

 of France ; traverses the whole of Portugal and Spain ; 

 includes nearly two-thirds of Germany ; passes through, 



* The dry land, according to some French geographers, is divided into three teorldi, the Old World, New World, and Maritime World ; 

 and these are subdivided into eight divisions or parts. 



The old world, in the eastern hemisphere, extends from south-west to north-east, and comprehends two continents, viz. Africa and Asia. 

 and Europe. 



The new world, in the western hemisphere, extends from north to south, and is composed of two continents, North and South Ame- 

 rica. 



To the south-east of Asia, there is a mass of land nearly as large as Europe. It is Notasia, or New Holland. It is surrounded with 

 many islands of great extent, and with smaller groupes of islands, that extend to the vicinity of the New World. This is named th 

 maritime world. 



The maritime world is composed of three distinct parts : 1, Australasia, which includes New Holland, and the great islands that lie to 

 the east of it. 2. The great archipelago of islands to the south of Asia, named the Archipelago of Notasia. The third, which is named 

 Polynesia, includes the islands scattered through the great Pacific Ocean. 



Those islands situated near continents are considered as belonging to them. Thus the British Isles belong to Europe ; those of Japan 

 to Asia; the West India Islands to America; Madagascar to Africa. But there are other small islands situated in the middle of trie 

 Great Ocean, and which cannot be referred to any of the preceding divisions. These may be named Pelagien, and belong to the oceans in 

 which they are situated. 



Great islands like continents have their high chains of mountains, rivers, lakes, forests, deserts, and large animals. 

 In the island of Sumatra, which is only a secondary one in point of magnitude in the Archipelago of Notasia, we meet with the elephant, 

 rhinoceros, and hippopotamus ; but the species of animals are often different from those of the neighbouring continents. Thus the rhino- 

 ceros of Sumatra is different from that of Asia and Africa. Madagascar produces that singular species of sloth named at, and the diffe- 

 rent species of makis, which we do not meet with in Africa or elsewhere. The inhabitants of Van Dieman's Land are very different from 

 those of New Holland; and the greater number ofmammiferous animals and reptiles are specifically different from those met with on the 

 neighbouring continent The dog, which is so much prized, and so generally distributed, is a stranger to them, while it is met with very ge- 

 nerally in New Holland. Islands of a moderate extent have no great animals, and their rivers are smaller than hi those of the first magnitude. 

 The smallest isles are simply rocks, without rivulets, or even springs. Their precipitous cliffs and caves are sometimes beautifully or- 

 namented with madrepores, and with fuci of various beautiful colours and elegant forms. Their summits are inhabited by pelicans, cormo- 

 rants, albatrosses, frigate birds, and a host of other marine birds ; and during tempests they are lashed by a furious and highly phosphoric 

 ocean. 



As these three worlds are narrow towards the south, and broad towards the north, it follows that the northern hemisphere contains the 

 larger portion of land, and may be called the terrestrial ttemitphere. The touthern hemisphere, which is very much covered with the water* 

 of the ocean, may be named the maritime hemisphere 



