BY W. N. BENSON, W. S. DUN, AND \V. R. BROWNE. 295 



cuesta, formed of a' sheet of igneous rock over three hundred and fifty feet in 

 thickness, tlie western dip slope and almost vertical eastern scarp being very dis- 

 tinctive (see Text fig'. 3.) South of this, there is a small hill in portion llfi which 

 seems to be composed of a lenticular mass of tlie rock about two hundred feet in 

 thickness. Further south, in Sandy Gully, is a larger mass composed of both 

 vitropliyric and litlioidal andesite which together reach a thickness of nearly 

 fifteen hundred feet, and further south again, oh the margin of the map, is the 

 great mass forming Kingsmill's Peak, the thickness of which has not yet been 

 a-scertained. It does not seem likely that these isolated masses of pyro.xene 

 andesite are repetitions In* faulting of portions of the continuous median zone, 

 though perhaps not impossible. Strike faulting occurs to some extent, but its 

 fiill effects are unknown. Thus along the two lines of section north of Curra- 

 bubula Creek, the apparent thicknesses of the lower portion of the Kuttung 

 beds are respectively forty-two and forty-four hundred feet. Along the southern 

 line of section, the apparent thickness of these beds is only thirty-four hundred 

 feet, and there is additional evidence (see pp. 307-8) to suggest that the move- 

 ments differed on the two sides of Currabubula Creek, that some portion of the 

 Lower Kuttung rock was repeated by strike-faulting north of the Currabubula 

 Creek, or was cut out by the same process south of the same creek. The trun- 

 cation of the western margin of the andesite of King'smill's Peak suggests tho 

 latter as the more probable alternative. In either case, the exact thickness of the 

 Lower Kuttung Series remains in doubt. No fossils have been found in this 

 portion of the Series, unless tlie plants assigned to the uppermost Burindi rocks 

 should rightly be included here. 



The inclination of the beds is between 35° and 40° to the S.S.W. in the 

 northern part of the region, but less in the southern. 



Middle Portion of tlie Kuttung Series. 



(a) The Lower Glacial Beds. — Tliis is the most varied and interesting portion 

 of the Kuttung rocks in the district. The succession of beds has been traced in 

 approximate detail along four lines of traverse. In portion 223, a mile and a half 

 to the east of Currabubula railway station, a small cpiarry exhibits a very fine- 

 grained, almost porcellanous, creamy-white banded rock which has some of the 

 characters of the "varve" rock of De Geer (22) (see Text-fig. 3a, Section iii.). 

 Beneath and especially above it the bouldery rock is not a normal conglomerate, 

 but in place of closely-packed, contiguous, rounded pebbles, more or less uniform 

 in size, the pebbles present are sub-angular, very varied in size, and are set in a 

 matrix of gi-itty felspathic material, in which they are often widely spaced and 

 not contiguous, and there is little sign of stratification. The rock has thus some 

 of the cliaracters of boulder clay or tillite. Tliis bouldery material, with inter- 

 bedded tuff lying above the flne-gi'ained banded rock, is about 1000 feet thick, and 

 extends into portion 321 (Mr. Proctor's jiroperty). Above this is a second zone 

 of fine-grained banded rock, but here the comparison with "varve" rock is even 

 more marked. The bedding planes of this rock are often strongly contorted, and 

 scattered through it are small or large pebbles of granite, aplite, etc. — evidently 

 small erratics. This zone of "varve" rock has Ijeen proved to be continuous for 

 at least five miles, and is, therefore, termed tlie main "varve" zone; it is about 

 fifty feet in thickness. Lying above it are laminated, olive-green mudstones very 

 like those in the Burindi Series, but so far these have not been found to be fos- 



