16 



inures. Occasionally a small channel has been worn through the bat torn of thac di- 

 Tiding walla. 



On the SW-, where the structural plane* Are inclined inwards and (ho sheets of rock 

 between them are fulling olf P ihcre arc only a few well marked groates at the upper edge. 

 At one, place where the rock has less deeply exfoliated on one aide of a cross (Imperial plane 

 (i. c one perpendicular to the fact) than on the other to as to present a side of a few feet 

 braid at rifltit jinnies (o the face, a channel, about 3 feet deep and 1 foot broad* open tun 

 on this side and parallel to the face or the rock, shews dearly that here a par I ion of 

 the sheets has been loosened , nplil . and then fallen out. The bottom has afterwards been 

 worn rcucate from Ms- serving ns a ram channel 



The NW- fate, to far a* the rock continues nearly perpendicular , presents deep fur- 

 rows , and , whnn il incline? inwardly these disappear. 



The NE. face, being perpendicular or sightly inclined outwards presents d tan nets from 

 the summit to the base. 



The NW. mod 5\V, faec* may hare originally been grooved to the Mlom , as the 

 channels arc (on the latter very obviously) decreasing in length by the gradual ci folia linn 

 of I he rock m planes which intersect ftofa. The lower surface is fresh. Where the chan- 

 nels exist the rock has a black, grey or hoar antique look. If the channels arc altogether 

 owing to an operation which is still in prDrcrcfi«j the period required to produce Ihem must 

 have been very long* as the weathering now going on must bo extremely sbw, The tnrfac* 

 ii coverd with such q close vegetable covering f that it must, in preat measure, protect it from 

 the. jnni'hiitiiirijl action of the rain. Descending a litllo to the east of the spot where I hod 

 entered the jungle, I examined some large syeni lie masses which rose from the Leach, Ope 

 of these was divided by a chasm, and op one side, lo the breadth of a fool or more s and 

 on ihe other, to the? breadth oT S or 4 feet P ih* rock was n black hornblcndie basalt inclw 

 n»jlQ lei flinty, similar to that before mentioned. This must originally hive been a connec- 

 ts I , -iifi.: or dyke about G feet broad. The basalt has been freshly quarried urn! this alone 

 limited place exposed the line or junction of the two rocks. It is sharp and well defined t 

 and on m-h side the rock* possess precisely the same character which they have at a dis- 

 tance from il. Some or the fragments lying around h however p exhibited (he two reeks blen- 

 ding at t In-- line of j unci ion somewhat in the manner of the specimen mentioned above p. 13 J 

 but frequently Ihin laminae of the basalt penetrate the crystallized per E ion of the rock. 

 From the very variable nature of the syenites and volcanic rocks of this Inland, and the 

 abruptness wilh which the proportion* of the constituent of the same mass often change 

 ?o as entirely to aller its aspect , I had been previously led to suppose y lhi{ the whole 

 belonged Co one and tbo same formation. The appearance of this zone at once pointed 

 to the eon tern poranity of its origin , and I have no doubt that is wag formed in the mode 

 , j i. ,LiiJ by Mr. Dhuwjs i. 3 > r vii by the opening of a figure in the syeni tic mass while 

 yul vueid into which the moat Ho id ingredient, hornblende, drained from the sides or rote 



{IJ U-D-.Mi nth Fdtiaie liflniU. p- 121 



