A(je of the Alkali Rocks. 155 



phonolites and trachytes at Port Cygnet (pp. 24, 26 and 27), and 

 tentatively referred them to the top of th^ Permo-Carboniferous 

 series. 



(3) Mr. Twelvetrees, in a paper, entitled " A Geological Excur- 

 sion to Port Cygnet," in connection with the Australasian Asso- 

 ciation for the Advancement of Science, 1902, published by Roy. 

 Soc, Tasmania, 1902, in the course of a report on the excursion 

 described the modes of occurrence and petrological characters of the 

 chief rock types then known, including in his report petrographic 

 determinations by Professor Rosenbusch. 



(4) Mr. Twelvetrees contributed a " Note on Jacupirangite in 

 Tasmania," to the Roy. Soc, Tasmania, 1902, in which he 

 described the occurrence of this rock among the alkali intrusions 

 of Port Cygnet. 



(5) Mr. Twelvetrees, in a paper, entitled " On the Nomenclature 

 and Classification of Igneous Rocks in Tasmania," published by 

 the Aust. Assoc, for Adv. of Science, New Zealand, 1904, pp. 264- 

 305, discussed the position of the alkali series in a review of the 

 classification of the igneous rocks of the State. 



(6) Dr. F. P. Paul published a paper, entitled " Foyaitisch- 

 Theralitische Gesteine aus Tasmania," in Min. Petr. Mitt., Vienna,. 

 1906, pp. 269-318, in which he recorded detailed chemical and 

 petrological work among the alkali series. 



(7) Mr. Twelvetrees made a " Report on Gold at Port Cygnet 

 and Wheatley's Bay, Huon River," published in Report of Secy, 

 of Mines, Tasmania, 1907, in which he associates the gold occur- 

 ence with quartz veins developed in the metamorphosed sediments; 

 of Lower Permo-Carboniferous age at the contact with the alkali 

 intrusive rocks. 



(8) Mr. Twelvetrees, in his " Outlines of the Geology of Tas- 

 mania," published in the Report of the Secretary for Mines for 

 1908-1909, pp. 133, 141 and 142, regarded as unsettled the precise 

 age of the elaeolite and alkali syenites, with various alkaline por- 

 phyries at Port Cygnet and along D'Entrecasteaux Channel, but 

 placed them at the top of the Permo-Carboniferous series in Tas- 

 mania, above the horizons of the Southport sandstones and shales, 

 and the Mt. Cygnet and Adventure Bay sandstones and shales, of 

 which the latter is correlated with the Newcastle series of New South 

 Wales. On pp. 141, 142 it is stated that the alkaline rocks which 

 form a S.W., N.E. belt running from the Huon River through 

 Port Cygnet to Woodbridge and Kettering, are referred provision- 



5 



