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country, resting apparently on the eastern side on the “ Star Beds,” and on the western 
on mica schists and granites. This area is thus described by Mr. Maitland in his 
Report on the “ G-eology and Mineral Resources of the Upper Burdehiu 
“ The basaltic lavas occupy an area of about two thousand square miles at the 
head of the Burdekin. 
“ The largest development occurs in the corner near the divides between the 
waters of the Burdekin and the Einasleigh, and between the Herbert and the Burdekin ; 
they form an extensive plateau, having an average altitude of about two thousand 
feet above sea-level. The western boundary of this immense plateau has not yet been 
mapped. 
“ Basaltic outflows are known to exist at Surprise Creek, a tributary of the 
Einasleigh. These, which emanated from foci, on the Burdekin- Einasleigh Plateau, are 
crossed by the coach road from Herberton to Georgetown, near Quartz Hill. This is 
distant about forty miles from the watershed of the Burdekin and the Einasleigh. 
“ The northern boundary has also not been delineated. Streams of lava have 
flowed down some of the existing valleys in the neighbourhood of Gunuawarra Station, 
and have been described in a previous rejjort.f Doubtless the hot springs therein 
described is but the ‘ dying gasp’ of that volcanic action which was at one time rife 
in this district. 
“ In addition to this immense plateau, there occur other isolated patches in the 
district, shown on the map. These lavas, since their formation, do not appear to have 
been very much affected by denudation. 
“ The basalt, of which the tableland is made up, occurs in a series of super- 
imposed lava-flows, emanating from numerous volcanic foci, which rise as conspicuous 
hills all over the plateau. 
“ The surface of these lavas is, in places, formed of ‘ chaotic heaps of angular 
blocks of basalt, tossed in every variety of disorder,’ rendering locomotion a matter of 
some considerable difficulty, especially with horses. Generally, the surface produces a 
luxuriant growth of vegetation, well suited for and much relished by stock. The more 
rugged surfaces of some of the more recent flows are covered \vith bottle-tree scrub. 
“ On the other side of the Burdekin, west from the Valley of Lagoons Station, 
the surface of the lava-flows is full of dismal-looking deep pits, of all dimensions, in 
which water often accumulates. The formation of these pits appears to be due to the 
caving in of the surface of a lava stream. The surface of a lava stream flowing from 
one of the volcanic foci cools and hardens, whilst the molten matter flows from beneath, 
leaving a tubular cavern ; in course of time, a portion of the hardened surface gives 
way, and a pit with vertical sides is the result. These caverns can sometimes be followed 
for a considerable distance ; they form excellent hiding-places for the natives. Water 
can often be seen and heard flowing at the bottom of these holes. Many of these large 
holes, filled with water, are met with on the divide between the Herbert and the 
Burdekin. In the whole of the area examined there was found no trace of a,ny 
fragmental rocks associated with the basaltic outflows. It is conceivable that denudation 
may have removed all trace of the more incoherent material ejected ; but still it is hardly 
likely that in an area of two thousand square miles there would not be some fragments left 
“ Professor J. D. Dana,t in the course of his studies in vulcanology, has concluded 
that basaltic lavas are but rarely associated with fragmental deposits (ashes, cinders, and 
* Brisbane: by Authority : 1891. . , 
+ “The Geology of the Coolgarra Tin Mines and Surrounding Districts. A. Gibb Maitland. 
Brisbane : by Authority : 1891. 
$ J. D. Dana, Characteristics of Volcanoes. London : 1890. 
