GEOLOGY. 



arc certain to be left unrefiitcd by others. And who 

 would be defirous to wsfte his time in refutins^, or even 

 remembering, all the theories of the earth now rxtnrt ? Their 

 number, amounting already to above half a hur.died, ap- 

 pears to be daily increafmg, and ftands ir need of clafliiica- 

 tion to afilft the memory ; which, it m.ull be allowed, might 

 be more profitably employed in retaining thofe general obier- 

 ■v-ations which, nnconneftcd wth any theory of the earth, 

 or with the Mofaic account, have in latter times been prefented 

 to the world by a fcv/ unprejudiced gcognofians. Inftead or 

 prematurely endeavouring to accommodate the little geog- 

 roftic knowledge we poffef'S to the events hinted at in the ia- 

 cred hyn-.n of creation, which was by no moans intendod for 

 a fyllem of gcologv ; we ih.ould conim.ence our rciearches m 

 this field of knowledge with fubjecting to a careful exam.ina-- 

 tion what nati;re produces as it were under our eyes, fuch as 

 the manifold alterations that have taken place in the phy- 

 f:ognomy cf trafts of country iilmoll within the memory of 

 man. How little arc we acquainted with the m.tans whuth 

 nature employs to form the very foil on which we tread, by 

 converting into m.ouid the various animal and vegetible 

 cxuvix ! How fcanty are the genuine oblervations we pof- 

 fefs on the proceCs of alluvial dcpofition ! on ths detritus ac- 

 cun-.ulated at the foot of mountains by means cf the decom- 

 pofitio!! of the various rocks ! how little do we know of the 

 procefs employed to produce petrifactions ! and how little of 

 the circumilaiices under which the latter occur ! And yet 

 many of thefe, and other phenomena with.in the fphere cf 

 human obfervation, will admit of confiderable elucidation, 

 and may lerd to very intereftingrefults, by applying to tlicm 

 found princij-lcs of logic and iiiduAion. But refcarches of 

 this nature require what few arc inclined to bellow upon them, 

 tl-.e patient obfervation of many years ; and, v. hat falls to 

 the lot of few obfervers, a facility of com.bining and Gene- 

 ralizing infulated k&s. As an inllance both of the difficul- 

 ty and utility of fuch refearches, if properly condudk-d, 

 and of the little attention that has hitherto been paid to con- 

 fiderations that {hould precede any attempt at fram.iiij^ a 

 fyRem of geology, wc advert only to the highly interefting 

 difcoveries made within the laft tvs-clve years, by Cuvier in 

 the neighbourhood of Paris. It is in the confined fpace of 

 the well known sryps-formation of that part of France that 

 this incomparabie'naturalitl has found the offeous remains of 

 no lefs than fifteen quadrupeds, unlike any fpecies novxr known 

 to exia. .-Have thefe organized beings, it may be afced, 

 lived in the places where their remains are found, or have 

 they been carried thither ? and are they ftill to be met with 

 hving, or to be confidered totally or partly dellroyed .' It 

 18 obvious that the caufes to be afligned for the occurrence of 

 thofe petrifactions muft be diametrically oppofite according 

 as thefe two fimple queftions are anlwered in the affirmative 

 or negative ; and yet fomebody has thought it worth while 

 to fatisfy himfelf refpecting this circuuulauce ; nor have any 

 of the authors of the ten or twelve hypothefes that profefs 

 to explain the formation of the bafin of Paris, besn av.-are 

 that in a folitary fmall corner of that bafin, namely, at Grig- 

 non, there have been difcovered by Lamarck, in the courie 

 of feveral years, about fix hundred unknown fpecies of 

 (hells, befides forty or fifty, of which the prototypes are 

 fuppofed to be ftill exilling. 



We (hall not attempt in this article to give a hiftory of 

 o-eology, which v/ould be nothing more than a chronological 

 expofition of the different theories of the earth (fee 

 Eahth, and Theories of the Earth): nor is it to naturalif.s 

 of earlier periods than the latter end of the lad century, 

 that v,e are indebted for genuine obfervations in this depart- 

 ment of fcience. But mucli as we owe t-o the exertions of 



a Lehmann, Deluc, Dolomieu, and particularly Sauffur?, 

 who, in his celebrated agenda, has proved how ^vell he knew 

 the dcfiderata of geology, and what remained to be done to 

 give this branch of knowledge all the perfeAion it is fuf- 

 ceptible of ; yet the merit of arranging, into a harmonious 

 whole, a multiplicity of materials furnifhed by an intimate 

 acquaintance v;ith the internal ftrutture of a confiderable 

 and highlv interefting traft of country, is entirely due to 

 Werner ; \vhd, being affifted by the moft profound know- 

 ledge of the various mineral fubftances, and gifted with a 

 happy facihty of generahzing facts, has produced a fyftefu 

 of geogaofy, at once iimple and pradical, and much more 

 free from gratuitous aftum.ption than all the reft. Profe'for 

 Jamefon is the firft in this country who has given an expofi- 

 tion of the Wernerian geognofv, conltitutii;g the third 

 volume of his "Mineralogy." The following is intended 

 only a-, a brief n<etch of that fyftem, fuller details of which 

 will be 'ound under the various articles referred to. 



The furface of the globe, confidered relative to its in- 

 equalit'es, is divided into highland, lowland; and the bottom 

 oftliefea. The /^/j/r.'^znJ comprizes, i. Alpine land, core.- 

 pofed of m.ountain groups or feries of mountain chains; 

 2. Mountain chains, formed by a feries of thofe ftill ir.ore 

 fimple inequalities, called 3. Mountains : in the form.er 

 we confider their length, height, fonn, and conncttion ; the 

 parts of the latter are the foot, the acclivity, and the fummit. 

 See Mountain.^, and Mountain Groups. 



Loivland we call thofe extenfive flat trafts which are 

 almoft entirely deftitute of fmall moimtain groups, which 

 latter, if they occur in them, generally occupy the middle 

 part of the lowland. The principal lowland in Europe is 

 the eaftern part of Great Britain, the north of France, th.e 

 cidevant Neth.erlands, the northern part of Germany and 

 Silefia, the whole of Poland, the N. W. part of Ruilia, 

 towards th.e Ural mountains, a very fmall part of Sweden, 

 namely, Gothland. The fecond extenfive lowland plain is 

 in the centre of Afia ; it is known by the name of tlie 

 Steppes, and includes almoft the whole N. E. part of Ruffia ; 

 fome fmaller ones are in Arabia. The extent of the low- 

 land of Africa is not known. America has two confiderable 

 lowland plains : the one, in its northern half, is traverfed by 

 the iMilftfippi and Mifouri, and borders towards the eaft 

 by the Apalachian m.oimtains, and the W^eft India ifiands ; 

 the fecond, in South America, borders on the Andes. 

 With thefe plains of the lowland are connected the rlver- 

 courjh, or river valleys, in which we have to confider the 

 bed of the river and the holm or hangh land, the high and 

 low bank of the river. (See ^i\F.\\-courfe.) The incon- 

 fiderablv rifing ground with which the lowland plains are 

 frequently marked, is, by German geogncfians, called 

 Land-h'ohtn wh.en they are nearly of equal length and 

 breadth, and Land-riicken when the)' have an elongated 

 form. 



The bottom of the fea, or that part of the globe which is 

 ftill covered by water, may equally be confidered with a 

 view to its depreflions and elevations ; to tlie latter belong 

 ihe fiat, the rocky bottom, the flioals, reefs, and ifiands. 

 See Se-\ and Island. j 



It is only after a diligent ftudy of the inequalities juft. I 

 pointed out, that we can with advantage undertake to 

 explore the means employed by nature to produce them ; 

 and the firft ftep is to proceed to the examination of the 

 phyfical caufes of the flow, but unccnllng changes of the 

 globe. Obfervation teaches us, that moll of the elevations ij 

 and hollows we meet with on the furface of the earth owe: \ 

 their origin to the aftion of the atmofpherc, to that of the I 

 ocean, and to vgicanic fire. Thefe pov/erful agents may he " 



confidered 



