516 
“ I met witli sandstone, belonging to the same series, containing tlie Cretaceous 
fossils Avicula alatu, Leda elongata^ and Kiwula, &c., &c., about thirty-two miles 
north-west of Bundaherg, and about ten miles south of Eosedale Station. Their dip was 
uncertain, but they were evidently overlying the [Burrum] Coal Measures Series, which 
is exposed about two miles south, in Littabella Creek, dipping 12° to the N.E.” 
Mr. Rands writes me under date I6lh September, 1889 ; — “ I have come to the 
conclusion, after another examination, that the Maryborough Beds have been brought 
into their present position by a fault, and that they are unconformable with the Burrum 
Series, occupying some local hollow, as shown in the section.” (Plate 46, fig. 3.) 
Professor Ralph Tate, of A delaidc, after a careful study of the Organic Remains of 
the Cretaceous rocks of South Australia, records his o^tiuion that the Maryborough 
Beds (Queensland) are of Cretaceous age.* 
In a Report on the “ G-eological Peatures and Mineral Resources of the Alackay 
District” t Mr. Maitland describes as follows certain “rocks probably the equivalent 
of the Desert Sandstone Series”; — 
“ The rocks mapped as being the equivalents of the Desert Sandstone Series are 
classed with them more on account of their analogy to rocks of that age in widely 
separated localities thau any stratigraphical or paleontological evidence collected would 
warrant. Jfowhere arc they seen to rest upon any rocks the relative age of which has 
been satisfactorily made out, and all that can bo at present said of them is that they 
overlie unconformably all the other rocks of the district, save upon those referred to 
Post-Tertiary age. 
“ The strata consist of a series of trachytic lavas and subaqueous ashes, seen at 
several localities in the country to the north of the Pioneer, and about four hundred 
and fifty foot of sedimentary rocks, occurring in the cliffs forming the Cape Hills- 
borough tableland, and an isolated fragment of coarse conglomerate near Cape 
Palmerston. 
“ I'he lavas and ashes will be dealt with first, as in all probability they were 
formed in the early days of the history of this period. 
“ One of the most conspicuous examples of the lavas is to be found at Mount 
Mandarana, better known as the Black Gin’s Leap, close to the Bowen Road, about 
twelve miles north-west of Mackay, where it forms a broad table-like mass, rising to a 
height of 650 feet, by corrected Aneroid, above the level of the road. The rock of 
which the Leap is made up is lithologically a trachyte, and may be generally described, 
when examined with a lens, or the unaided eye, as consisting of a light-coloured porous 
matrix, in which crystals of sanidine and minute crystals of what appear to be horn- 
blende are embedded. It is seen (Plate 46, fig. 1) to rest upon black shales, at a 
point in a gully flowing from the north-west corner of the mountain three hundred feet 
above the road. At the junction of the two, the shales for a few inches are slightly 
hardened. The lower portion of the sheet is made up of rudely hexagonal curved 
columns, the outward curvature being northwards. The structure of certain parts of 
this rock would seem to imply that in reality it is a succession of lava-flows of variable 
thickness ; the estimated thickness of the sheet is not less than three hundred and 
fifty feet. 
“ On the low hills on either side of the road, at no very great distance from the 
Leap Post Otfice, a bed of fine-grained, yellowish-white, ashy sandstone, with scarcely n 
trace of bedding, is seen to oveidie the sandstones and shales. (Plate 46, fig. 1.) Rroni 
* On the Ago of the Blosozoie Rocks of the Lake Eyre Basin. Proc. Aiistr, Assoc, Adv, Set'., 
1888 , p. 228 . 
t Brisbane : by Authority : 1889. 
