Correspondence—F. Chapman. 479 
(4) That waters heated to no more than 96° to 139° F. are, by 
reason of their temperature, ‘plutonic’ waters. (p. 317.) 
(2) The impossibility of the derivation of the oil or gas of, say, the 
Alice Downs well from intercalated sedimentary beds. (p. 318.) 
(m) That tidal wells are entirely analogous to geysers. (p. 328.) 
(x) The impossibility of water percolating from overlying sedi- 
mentaries into fissures in granite (Oxton Downs). (p. 339.) 
(0) That ‘‘if the water be of meteoric origin, it must continually 
be enlarging the underground fissures” (p. 340), and this despite the 
weight of 2000-4000 feet of strata already quoted by the author 
(p. 289) as a sufficient cause of flowing wells. 
‘Professor Gregory throughout assumes— 
(p) The impossibility of meteoric waters descending to sufficient 
depths to gain the temperature observed ; and 
(q) The impossibility of the observed gases and contained solids 
being derived from chemical interaction within the sedimentary strata. 
Finally, Professor Gregory loses sight of the great facts that thousands 
of square miles of the granite through which his ‘ plutonic’ water is 
supposed to have come is exposed to our investigation, and that the 
granite is presumably now in exactly the same condition as during 
the Tertiary period, when his waters were accimulating. While 
the fissures in the upper 500 feet of this granite contain water, as in 
the Queensland and Westralian mining fields and in the numerous 
bores near Camooweal, yet whenever great depths are reached, as the 
2,600 feet at Charters Towers, with lesser depths on other Queensland 
fields, and the 2,000 feet of the Coolgardie bore and the Kalgoorlie 
mines, the granites and older rocks are dry. But Professor Gregory’s 
theory demands, in view of the daily yield of 450,000,000 gallons, 
a widespread present distribution in the granite of fissures filled with 
hot water and extending to great depths. 
With the foregoing protest against the elevation of pure assumption 
to the commanding position of ascertained fact I am content to leave 
the full discussion of the subject to the capable pens of my former 
colleagues in Australia, who have had a wider personal knowledge of 
the artesian area than I possess. Matcozrm Mactaren. 
NOMENCLATURE OF AUSTRALIAN SILURIAN OPHIURIDS. 
Sir,—A few points in Dr, Bather’s article ‘‘ Australian Palzonto- 
logists on Silurian Ophiurids”’ call for further comment. Taking 
Dr. Bather’s remarks serdatim, it would appear that I had flagrantly 
transgressed certain established rules of nomenclature, since he says 
that I seem ‘‘for the moment to have forgotten the perfectly definite 
and, one had thought, universally accepted rule of nomenclature, 
according to which the genus must. follow its genotype. In other 
words, Sturtzura must become a simple synonym of Protaster.’’ In 
changing the genotype, reference was made to the Stricklandian Code 
of Rules of Zoological Nomenclature (which forms the basis of the 
several later codes), where, in paragraph 5, it says: ‘‘ When the 
evidence as to the original type is not perfectly clear and indisputable, 
then the first person who subdivides the genus may affix the original 
