cd ft or only 2 ingredients ; but in by fur the gr&aler number certain plates or ItaLys „ 

 m it were j contained a ■ ;■ rt-it C c r proportion of due ingredient , and certain portions a 

 greater share of the other 7 forming thus what by »mc is called Gneiss. The length of 

 these plate* is always disposed parallel to lira general direction of tho stratum, and the 

 edge* •«« vertical, or nearly *o. There were also other stones, id which the component 

 matters Were disposed in whal ltiny be called HtrLae ; that is a great proportion of one of 

 its component ports run horizontally through the others in lines parallel to each other j 

 mid 10 £ In: direction of (he stratum* Such sloncs ba^c also been included under the name 

 of rjneiia. 



: hi m.uiy «f these stones ir: IJ be -xv i i -rs :iv found rcriical Ljlyi'ta of vvhil^ Til ijiinrlv., 

 miming pur.ilM I-* liif 1 Mm Mini, und i/nHrdy sppiiwli nj nnc 1 1 :a r r u|' live BgQTegltod mnK^r 

 from the other, without producing the smallest interruption of substance; nor is the stone 

 more easily broken there than anywhere else. In these stones, when entire, there in no- 

 thing like a scJiiHtosCj or striated rraelurej hut in a state of decay j if eiposcd to the weather 

 in certain filuatiuus especially so that the rain may lodge mi I hi; flurfaofj^ the ftfOEle gradu- 

 . 1 1 1 v- p I l f s 1 1 l C - - ihifJ pl iI' liLi^ ^ole , and this seem* to happen ;v> readily to pure quart* , 

 or to perfect granite* and granitels,, ai to the gflifiiit, In other caset ntfaiuj capcciaSly where 

 blacks have been detached, the stone decay* concentrically and of course } losing its angles 

 fiitt, becomes a rounded mass (1)/' The rocks of what Dr. llianiTo* terms the northern 

 intermediate division consist alio of granites and gneiss. 



The recent publication in the Journal of the Asiatic Society of Bengal f of Captain? Hsuieit^ 

 Report hit mi ncra logical survey of a portion of tho Himalaya* (-) has shewn 1 1 h ;l t [fticiss is 

 the grand constituent of these stupendous mountains., bat the fncfct frequently loses its la- 

 minar character and approaches or passe* into [jraoiti:; a upecic* of granitic f rutins h common, 

 ttIii el i appear* wry often to form the transition between granite and gneiss. The obserta- 

 lions of Captain Mini hurt nppcar to me to lend Tery strongly to the conclusion that toe gneiss 

 and granite or the Himalatfat were of contemporaneous plutcnic origin. Tho gncissosc strut* 

 lure may be simply the confterruenco of an excess of mica, for in most instances where Captain 

 liiu&Lf notices the occurrence of [jranite. lie adverts la iho dioiiuuliooj of the mica, Again, 

 as mica diminishes the hi id iiar structure disappears. Thus at one place the gneiss gradually 

 I uses its mica and becomes an unlaminatcd mixture of quarts and felspar , huTinrr the ngpect 

 of qua r It rock. A rock occurs composed of fclipar and bornblendo in dLETercnt proportions 

 apparently rery similar to some of the Pufo Uhin varieties; nnd at one plaee Captain St, ob* 

 served it pasting into gneiss., althougli in general the transition is abrupt Jt occasionaly con- 

 laiiiti inifa :ind r.ro.ii t[itnr[T. m GreenKhito paWojj intn ^recnAtuue occurs frrcjuenliw The direc- 

 tion of ttie principal beds into which the gneiss is separated {(rue strain according to the Wer- 

 ucrnm* nud metatnurptiL^H.) coincides iTilh thai of the fnouiilain lone of greatest elcTftliOB., 



(A) Ths Jul* of Hfl iiirrpj n*t gir^n. but CapEaJd IIiimiit vh it AlmamA r «d|igti io it when flbtcp 



IttLit tinL^J L Ire iT.^ji.hinK \a J U Vl . I Sit- Hmn'i JuuriiiiL!. 



2a- 1 - dih, 1647 E 



