478 Correspondence—Dr. Malcolm Maclaren. 
show as briefly as possible, from ‘‘The Dead Heart of Australia” itself, 
that much of the data on which Professor Gregory relies, and to which 
he often gives the value of established facts, is pure assumption. 
Professor Gregory assumes :— 
(a) That subterranean waters may be derived entirely from cooling 
magmas, and that the steam issuing from volcanoes is so derived. 
(p. 286. 
(6) That the majority of important ore-bodies are due to ‘ plutonic’ 
or magmatic waters, and that, as there are numerous ore-bodies near 
the Australian artesian strata, there is consequently an abundance of 
‘plutonic’ water beneath. (p. 287.) 
(c) That, notwithstanding the general synclinal arrangement of the 
artesian strata (so far as they are known), and the unlimited motive 
force presumably inherent in ‘plutonic’ waters, these ‘plutonic’ waters 
would be retained within the strata. Mound springs and hot mud 
‘springs certainly do occur, but their yield is microscopic compared 
with the hundreds of millions of gallons the artesian beds are capable 
of furnishing daily. Further, it is assumed that there is a complete 
analogy between the retention within the strata of the Australian hot 
artesian waters and of the oil and gas of the Caspian and Pennsylvanian 
districts, despite the synclinal arrangement of strata in the former case 
and the anticlinal arrangement in the latter. (p. 287.) : 
(d) That flowing wells may be due to the pressure of an overlying 
‘sheet of impermeable rock, citing in illustration a tin bottle filled 
with water, the mouth closed with the exception of a pinhole, and 
pressure then applied to the side (p. 289). The analogy is mexact, 
since the pressure existed before the water-beds were filled with the 
water they now hold. 
(e) That the calculations for rainfall, surface evaporation, and 
percolation in the neighbourhood of Lake Eyre and in Central 
Australia are applicable to a water-bed there 2000-3000 feet below the 
surface, or to an intake area far away in Eastern Australia. (p. 325.) 
(f) That a complete analogy exists between the cold waters of the 
quicksands of the Kilsby tunnel near Rugby and Australian artesian 
waters (p. 300), yet the latter have gained heat and hence power. 
‘(g) That the disposition, dip, and character of the deep water- 
bearing beds are so well known as to preclude the possibility of 
irregularities in bore pressure being due to these factors (pp. 305 et 
seq.). But, for example, there may exist at no great depth beneath 
the surface a north-west prolongation of the Paleozoic rocks that 
outcrop west of Thargomindah. Some little support is given to the 
supposition by the shallowness of the Tonko bore, only 250 feet deep. 
An anticlinal arrangement of water-bearing strata on such a granite 
ridge would, from the flood-waters of the Barcoo and the Diamantina, 
feed both a Lake Eyre artesian basin and the great central Queensland 
basin. The geology of the region is, however, unknown. 
(A) That the salinity of the unknown beds traversed by the under- 
ground waters is practically uniform. (pp. 312-314.) 
(7) That there are known and well-established criteria of ‘ plutonic’ 
waters; that ‘mineral waters’ are of necessity ‘ plutonic’ waters; 
and that the presence of alkaline carbonates in waters is a sufficient 
guarantee of their ‘ plutonic origin.’ (pp. 315, 316, 339.) 
