Litchfield enquirer., 1835-09-03
LECTURES ON GEOLOGY, Bg PnetessOr SillimGH... Enos, fhe Salem Landmork.

en Trap Rocks. Hs said the difficulty in re-
 gard tO their fortDatien might be explained by
 inc suppOsifiOn that they had been pr0tru-
 ded from the bottom of the ocean. an the
 Iifst chapter of Genesis it is stated that the earth was once liqaid mass.--7he spirit of God nssUed upon tke (aee cf the wniers; and al a subsequent period the dry land isa said To have appeared. Aside from the authority of scripture. the geolOgist, from simple exam
 ioatiOn of the. appearances of the earth,
 would infer that it had been submerged; or
 in other words, that there had been deiuge.
 Had not the Trap Rocks been melted under
 an enormous superincnmbent pressure like
 tbat Of the ocean, they would exhibit very different appearance from the present one i: their suFlaee would have been inflated, ,intn- Snesesnt a0d seQfiated. ss 10 .sg st45G . Marked changes are produced by the Trap on the rocks through which 1t passes. It turns coal into coke or charcoal; it crystal ixes sulphur; and turns clay sandstone into brick or jasper. The lecturer described col unans 0f this rock which are about two miles from the city of Harford, Conn. These col umns rest on sandstone at the junction they are inflated just as their whole surface would have been, had they not been melted under asatsr. Mir. Silliman said it was impossible tO explain the facts connected with the Trap rock. but on the principle of fire that had once Fendered if liquid. a4 e,.,s.9 ss.4
 He then proceeded to the history of ,ihe Granite, the fundamental rock of the globe. With Broigniart's map he exhibited the diff tefent layers of rocks as they exist in the crust of the earth. He illustrated the differ enee between stratified and unstratified rocks by reference to two loases of bread, ,sthelone being cut in slices representing the stratiied, and the other not cut representing the unstFa- tiiied rocks The origin of this is from fire and water. It was water that made the lay. era. There were nechanical and chemical influences in these formations. There was erysfalixati0p, which is the result of fscohe-i sion from chemical solution. Some ofihej rocks .tsefe entirely subject to the chemical process others to the mechanical; and others still 10 the tep powers c0nabinbEi. syDn X N
 Granite is made mp Oftliree substances, via. qnartx. consisting of silex, one of the, most imperishable things in our world felspar, not quite 90 hard as quartz, and composed of two thirds silex, and the remainder aiu- mine and aikaii. Feispar is found in great abundance in Chester, Penn. and is manufac- \ tured into porcelain. The third substance entering into the forsnation 6f Granite, is mica. or isinggiass. unlike all other minerals, in being perfectly elastic 8Of1the three stib- N stances constituting granite quartz is grey. lelspaF white. and mica black. s:itsmt 1aa1
 The ancients were well tacquainiedG with granite. POmpeyss Pillar and Cle0patsa's Needle were made of red granite. To de- tesaine whether a bed of granite will be da- :s:shie for use, it is only necessary 10 see wketi er it has endured the sHatts of time. If 1t lias not been decomposed where t has beeH expo -sed to tho action Of the weath5r, then 1t ihay a,u concluded ahat it will proye goOd for b,.I-i dlng. layls A7uiBcy quarry is SirIiitu gtsnite.
 When mica is wanting in granite, lt.ist called 6lenlte. 3slsl 3st.iW aalsa9aarQ 1ot azDna
 The position of granite is, below all other rocks, though 1t occasionally rises above them alL z Mount, Blanc, Mount Washington and the Rocky Mountains, are granite. This the surface rock, as any rock may De. 3 tu v : .No animal or vegetable senSains are found in the granite, trap, ssrpeniine.l poSphyry or soap sione rocks. . Hence they Arsf called primitive as they are believed ioI have been termed before there were apyl apiuials pgyeg- elablcs. To the granite family belong gneiss and mica slate. Gneiss is n admirable rock for architeetnre. various in lis appearance, lying next 10 granite. and The frat that is stra- tiffed. Mica slate is Of the form of the I9aves of book, and is easily split. and Is dtstitute of felspar. In this rock are G,,ihd bgctns Known by the names of lheryl and garneL.-- Granite. gpeisssaph mica slate aretthe found ] ftion af fhe world. MOst of lhs rocks io Nsw- England belong 10, the granite family.
 Upon these are piled the common slate. of which ihe best for. use should De distinguish- I'd by thinness. firinncss. sno0thness, and olh. absence of foreign minerals. The best com mon slate is from Wales. There isl also she { chiosidsss slate. shei hernblend 6slste.a she hope slate. and ihs taieose slate, which Is solt and easily broken 1; and there is alsOdhe pagne- sia slate which some famishing inhabitants of sasage eonnlgiss ara said 10 eat, Irop is found in fhs slate at Williamsburg in this state. M
 Op closins his description of the slate, BIr. Silliman said he had sane through with the histOFy of the IFimitise rock s. so called, be- cause they are iyfestimed tO havep been lorif- ed aatsfi6r tN inc other ForksaaAst sibe tisss- iOFy s6f their formation, he said that fire had slss principal liass6cys thatlgeologists consid. cred them ass the DndOuhted product yf fire; though slaty and eryslalized rocks should br Fsgardsd ss ihe joint produe,i9n of Ire and water. '.
 A part of the primary seEies.i is fhe stasuardy marble, or primary iimtstone, which is most
 hsautifully dep6aited in New EnGland. espe- tt is very rare in Old Englanda Beds SOgSif
 aFs elegansly sisuased betx cen. .Ahe, ,slrata, of
 Daeiss and miea slAtessa Being, in cnsn,,any
 Milh the primary Feeka it is called primary.
 though composed ,of diiferent snaterials from
 gFaei.e. haslqg ePlcasssas lime, and sasbonlc ss1 fS. . s ga.. fsg ..sS a ,e lih .-l.y