FIRST EXPEDITION 477 



were formed by the lofty ranges from which the Annan, Normanby 

 i and Laura Rivers take their rise. North of this limit, or ancient 

 I shore, all the mountains which rise to the height of about 800 feet 

 I above the level of the sea " catch " (to use a graphic mining term) 

 I the even bottom of the sandstone, while from those which do not 

 j now attain this altitude, as well as from the valleys, the deposit 

 { has been entirely removed by denudation. 



With one notable exception, the sandstone, from the Byerstown 

 I Road northward to the Morgan, rests upon a foundation of nearly 

 | vertical strata of alternating slate, quartzite and greywacke. 



A thick and valuable bed of LIMESTONE is crossed by " Coward's 

 | Track " between the head of Oaky Creek and Mount Byerley. 

 ' [Mount Byerley is in Map G. R. L. J.] Should this limestone 

 i be traceable to the south, it may yet serve a useful purpose in 

 i defining the horizons of the accompanying strata. The edges of 

 i the slates and other upturned strata bear, for the most part, north 

 ! and south. Southward on this line of strike the stratified rocks are 

 I at intervals metamorphosed into, or pierced by, granite rocks. 

 I The auriferous districts of the Upper Normanby, Hodgkinson 

 | and Mulgrave lie nearly in this line. 



The exception referred to occurs in the valley of OAKY CREEK, 

 j between the Palmerville and Byerstown Roads. There the sand- 

 I stone overlies, not the slates and quartzites, but a great thickness 

 I of strata containing Glossopteris, the characteristic fossil fern of 

 I the New South Wales and Bowen River Coal Formations, and 

 I comprising sandstones, black shales, and coal-seams. This forma- 

 I tion has already been described at some length in the two reports 

 I above referred to. The beds dip at high angles to the north-west 

 I under the horizontal sandstone of the " Brothers," which is 

 I therefore separated from them by a violent unconformability. 

 { As a great thickness of the coal-bearing strata dips under the 

 j sandstone of the " Brothers " on the east side of that range, and 

 P does not reappear on the west side (where the sandstone rests imme- 

 j diately on slates), the coal-bearing strata must be bounded on the 

 j west by a fault which passes beneath, and does not disturb, the 

 i horizontal sandstones. The Glossopteris-bearing beds had been 

 j contorted, faulted and denuded prior to the deposition of the still 

 | undisturbed sandstone processes implying the lapse of animmense 



period of time. 



^ The horizontal sandstone varies in texture from a Jcoarse 

 t grit to a fine, hard, compact rock. The materials are for the 

 j most part siliceous, but occasionally felspathic. Generally white 

 I or yellow, they sometimes have a faint red tinge from the pre- 

 | sence of peroxide of iron. Where much iron is present, nodules 

 ! of fine hematite are frequently met with. Pebbles of quartz, 

 b quartzite, slate, Lydian stone, greywacke and granite occur near 

 : the base of the formation, forming a few beds of conglomerate. 



