MINERALOGY. 



393 



G*noy. the greater part of Italy ; and also part of Hungary 

 s^-y~ ' and Turkey ; and terminates on the borders of the 

 Black Sea. The course of this high land determines 

 that of the great low land. Saxony lies nearly on the 

 border of this low land or plain. It passes through 

 the north part of Saxony, to the East or Baltic Sea. It 

 also passes by the foot of the Hartz Mountains; 

 through the upper part of Westphalia : and further, 

 through the whole of Holland, the Netherlands, and * 

 small part of France : it even reaches the east coast of 

 this island. It extends very considerably towards the 

 north, including in its course Prussia, Poland, and 

 nearly all Russia in Europe ; and reaches to the Ura- 

 lian Mountains, including the greater part of Molda- 

 via. 



The other high land rise* in Norway and Sweden ; 

 comprehends a portion of Russia ; and extends, with 

 some interruption, to the Uralian mountains. 



High and low lands might also be pointed out in the 

 other continents. 



Coratituent ". Every high land is composed of what may be 

 p^,, [ termed alpine, mountainous, and killy land ; and some- 

 high Wad. times of small plains. The low Una, on the contrary, 

 consist* principally of plaint ; but we find in it, also, 

 sometimes mountainous and hilly land, and, very rare- 

 ly, small mountain groups. Here the constituent parts 

 are directly reversed ; in high land, the alpine country 

 forms the predominating feature, but in U>w land the 

 plain is the characteristic appearance. 



p. A I pint land is composed of mountain group*, or 

 group* of mountains. Each mountain group consists 

 of a umber of inequalities, which are denominated 

 mountain* ; and these are arranged into series, forming 

 what are called mountain chain*, or chains of mountain*. 

 A number of these chain*, when joined together in a de- 

 terminate manner, form a mountain group. Mountain 

 group* are thus excellently distinguished from the other 

 constituent parts of the high land. 





It is of much importance to be able to discriminate 

 a mountain group from others on which it may border, 

 or with which it may be surrounded. For facilitating 

 this discrimination it may be remarked, that mountain 

 groups are highest in the middle, and usually become 

 gradually lower and smaller towards the extremities ; 

 and that each individual group ha* a particular dircc- 



Mounuin 

 Miami. 



Mountain group* are sometime* separated from e*ch 

 other by plain* ; sometime* by valley* ; frequently by 

 mountainous or hilly country. 



10. Mountainous land i* composed of mountains that 



are 



into chain* ; but these chain* not con- 

 together by a central or high mountain chain. 

 Hence it never forms group*. It i* lower than alpine 

 land ; and is often intersected, which i* never the case 

 with alpine land. 



1 1 . The third constituent part of high land, namely, 

 Ij laad- Hilly land, is much lower than mountainous country, 



and consists of gentle, rounded, waved-like elevations. 

 These are sometimes arranged into groups. 



We have thus a complete scries, from the most ele- 

 vated and complete alpine country, through the raoun. 

 tainous end hilly, to the low country. 



12. In regard to the local situation of the constituent 

 parts of hin land, we may remark, that alpine land 

 ARM its principal constituent part, and that this is dis- 



from mountainous and hilly land, not only 

 by its frequency, but aW by height, and it* usually oc. 

 -u,,jir. ; . sWwmamvtMts/r 

 border* are marked by 

 VOL. xiv. PART n. 



the high land; whereas its 

 mountainous and hilly 



thus forming the transition to what is termed low Geognwy. 

 land. x- " "V"' 



1 3. The fourth constituent part of high land is plaint. 

 These are small, isolated, and rare ; and hence form but 

 unimportant features in the general aspect of high 

 land. 



14. Low land differs very much in its characters from ^o" lsnd ' 

 high land. It is principally composed of plains, and 

 sometimes contains flat hilly country, chiefly where it 

 borders on alpine country. Very rarely small mountain 

 groups occur in it, and these always occupy its middle 



part. 



1 5. As alpine land is very varied in its aspect, it will Particular 

 be proper now to consider its different parts somewhat d scri p* io 

 in detail. When a mountain group, or alpine land, is *| p " 

 viewed as a whole, it appears highest in the middle ; 



and this highest part extends through the whole group 

 without being intersected. This elevated portion is by 

 geographers denominated the high mountain chain, and 

 is one of the most remarkable parts of a mountain 

 group, because nature appears to have arranged all the 

 other parts as subordinate to it. It is the water-shed Wator - 

 for the whole of the neighbouring country, and is pa- 

 rallel to the length of the group ; hence the extremities 

 of the group are at the same time that of the high 

 mountain chain. 



All the other part* of the mountain group decline on 

 both side* from the high mountain chain ; and the in- 

 clined planes thus formed, are denominated the fall or 

 acclivity of the group. The inclination of the acclivity Acclivity erf 

 varies from * to 6*; that of the northern declivity of lh F^P- 

 tin- 1'yrenee* is from 3 to 4 ; that of the southern ac- 

 clivity of the Alps, from the line formed by the colos- 

 sal summits of Mont Blanc, Mont Cerven, and Mont 

 Rose, and of which the general height is 3500 metres, 

 to the plain* of Piedmont and Lombardy, is 3 J '. But 

 as such a general inclination is made up of many parti- 

 cular inclinations, on account of the inequalities of the 

 acclivity, we must, before we reach the summit, ascend 

 and descend acclivities much more considerable than 

 that we have just mentioned. The two acclivities of a 

 group have rarely the same degree of inclination ; on 

 the contrary, one is generally shorter and steeper than 

 the other. Thus, the northern acclivity of the Erzge- 

 berge is long and gentle, while the southern is rapid and 

 short. In the Pyrenees, the northern acclivity is more 

 extensive and steeper than the southern. The western 

 acclivity of the Andes is shorter and steeper than the 

 eastern. The lower part of the group, that which bor- 

 der* on mountainous and hilly country, is denominated 

 it* /bo/. When a portion of it extend* far into low 

 country, it i* denominated a mountain arm. We some- Mountain 

 times meet with small plains on the acclivity of the "" 

 group, and these may be denominated mountain plaint, 

 to distinguish them from those observed in low coun- 

 try. Very considerable heights sometimes occur in the 

 acclivity of the group, but these seldom reach the 

 height of the high mountain chain. 



The concavities, or hollows, in a mountain group are Valleys, 

 denominated talleyi. The valleys shoot from the nigh 

 sminlain chain, intersect the acclivity of the mountain 

 group, and terminate at it* foot. The valleys divide 

 the mountain chains from each other ; and by this di- 

 vision nature ha* formed all the varieties of structure 

 observed in mountain group*. 



The lateral chain* snoot on both sides from the high 

 Mountain chain toward* the foot of the group. Of 

 these lateral chains some are more considerable than 

 the most considerable, that which rim from 

 So 



