A GEOLOGICAL EXCURSION TO PORT CYGNET 

 IN CONNECTION WITH THE AUSTRALASIAN 

 ASSOCIATION FOR THE ADVANCEMENT OF 

 SCIENCE, 1902. 



By W. H. Twelvetrees, F.G.S., 



Go vernmerd Geo log i.st 



[Read May 12. 1903.] 



The interest attaching to tlie plexus of felspathoid rocks, now 

 known to occur at Port Cygnet, led to a flying visit being 

 paid to the locality by members of Section C. (Geology) of 

 the Anstralasian Association for the Advancement of Science, 

 in January, 1902. The occurrence of this division of eruptive 

 rocks in Tasmania is so restricted, and their development is 

 exposed so instructively, that a brief account of the excursion 

 will be interesting to others besides the actual visitors. 



Seventeen members took advantage of the opportunity, 

 and travelled to Port Cygnet by one of the Channel steamers, 

 making the trip in a few -hours. A call was made at 

 Kettering, in the D'Entrecasteaux Channel, where Professor 

 E. C. Hogg led the party to an exposure of Permo- Carboni- 

 ferous till, with glaciated pebbles. Oyster Cove, where the 

 belt of alkali rocks comes through from Port Cygnet, was 

 not visited, the entire energies of the expedition being 

 reserved for the better known area at Lovett. Elaeolite 

 syenite, essexite and alkali rocks with trachytoidal ground- 

 mass, occur at Oyster Cove. 



The assistance rendered to the cause of Science by the 

 Hon. Edward Mulcahy, the then Minister of Lands, Works, 

 and Mines, in lending the services of the two State geologists, 

 was appreciated by the members and duly acknowledged at 

 the time. Despite the short time at the disposal of some of 

 the professors, who had to return to Hobart to attend a 

 meeting of Council, the area examined was considerable, the 

 only regret being .that members could not linger a few days 

 longer at a spot which it was recognised must eventually 

 become one of classic interest to petrograjDhers. 



As the steamer drew near to the jetty at the head of the arm 

 of the Huon, known as Port Cygnet, about a mile south of 

 the township of Lovett, the scene was owned to be highly 



