HORN EXPEDITION — GENERAL GEOLOGY. 27 



following; tcniiH : — " At tlic lioltom an ;ifgill:n('(iiis seliist, aluivc many horiz(jntal 

 strata of a soft ai-gillacoous rock, oi^-iasioiiaJly iiitcrst ral ilicd witli a free sandstone 

 of various hues ; at tlie top was a stratum, not very tliick, of a peculiar siliceous 

 rock of a draU colour ; it breaks with a conchoidal fracture aiul looks like very 

 liard baked earthenware" (p. a). 



[The basal formatit)!! indicates an iniier of Pre-Cand)rian age; the intermediate 

 aryillaec()us series represents the type of the Upper Ci(Uaceous which prevails on 

 the northern confines of the basin ; the uppermost formation is of the usual, desert 

 sandstone, type.] The James and Waterhou.se llanges are constituted of a dark, 

 hard ferruginous sandstoiu; (p. 5). [The ciiaracteristic rock of the Larapintine 

 ►Series (Ordos iciau)]. \\i tlie gorge of the Hugh River in McDonnell Range " tlie 

 rock is a variety of gneiss of a very laminated nature." [This description is more 

 apt than that of Stuart]. 



II. — 8tuai;t, John INIacdougall, ••Journal of Ivxploralions iu 1858-G3," 

 L(.»ndon, 18G1. The tirst g<'ograpliical exploration of the legion under review was 

 by iStuart on three separate occasions end^raced in tlie years 1858-1862. He 

 descriljcs the a.xis of the McDonnell Range, particularly at Rrinkley Bluli', as 

 consisting of granite. 



III. — GossE, AV. C, "Exploration in 187o," Pari. Paper, S. Aust., No. 48, 

 1874. [The deternunations of some of the rocks referred to by Uosse are based 

 upon the exanunation of the original specimens in the jVluseum of the tSchool of 

 Mines at xVdelaide]. Tiie autiior describes the rock-structure of ^Mount Liel)ig, 

 the most westerly point of the McDonnell Range, as composetl of basalt, gneiss, 

 and .sandstone; strike E., dip 14" S. ; the rock (-face) perpendicular for 100 and 

 500 feet on south side. [The original specimens are gneiss, hornblende-schist, and 

 quart/Jte]. A granite ridge Ijetween Alounts Liebig and Udor has a strike 

 E. X 8., dip 4" .S. [A rock labelled Mount Udor is an example of Ordovician 

 quartzite]. The ridge of the West JJlutf Hills is composed of gnei.ss ; strike S.E. 

 x E., dip 81° S. Mount Palmer is composed of granite, gneiss, sandstone and 

 puddingstone ; strike W., dip 15^ north. [Rock specimens labelled King's Creek, 

 George Ciill's Range, are limonite and a fintvgrained compact sandstone of 

 Ordovician age]. " Ayers Rock is a high mass of granite IIUO feet above the 

 surrounding country." [A specimen labelled Ayers Rock is a small rolled 

 fragment of epidote-hornljlende.] 



IV. — GiLE.s, Ernest, "CJeographie Travels in Central Australi.i fi'om 1872- 

 1874," ^lelbourne, 1875. Tiie cliief geological records liy this explorer, whicii 



4.V 



