Revieivs — The Tin Field of North Dundas. 329 



V. — The Tin Field of North Dundas (Tasmania). By H. Conder. 



Geol. Surv. Bull. No. 26. 96 pp. and 4 maps. Hobart, 1918. 

 rPHIS area consists of a region of slates, sandstones, grits, and 

 J_ conglomerates, with volcanic tuffs, their early Palaeozoic age 

 being proved by the discovery of some badly preserved graptolites. 

 The mineralization appears to be due to the intrusion of a granite 

 magma of Devonian age, which gave rise first to porphyroids, then to 

 the main acid mass with a basic marginal facies: certain masses of 

 diabase may be of much later date. The metalliferous deposits 

 belong to several different types, as follows: quartz-tourmaline lodes, 

 quartz lodes, pyritic and pyrrhotitic lodes, and dolomitic lodes, with 

 other less well-defined types. The chief minerals are ores of tin, 

 lead, zinc, and silver, together with pyrite and pyrrhotite. 



VI. — Fossil Cockroaches. 



AMONG Mr. Bolton's energetic efforts to seek out all the Carboni- 

 ferous Cockroaches, we note the Manchester Museum publication, 

 No. 80, describes those specimens obtained by Mark Stirrup from 

 Charles Brongniart. These came from Commentry and are now in 

 the Manchester Museum. Among them is a fine dragon - fly, 

 Megagnatha odonatiformis. To these forms have lately been added 

 a series from the Pennsylvanian of the United States, described and 

 figured by Cockerell in the Proc. U.S. Nat. Mus., liv, 1918. Eight 

 in number, they comprise two new genera, Cobalohlatta and 

 Ptilomylacris. 



VII. — Annual Report of the Director of the Geophysical 



Laboratory, Washington, for the tear 1918. 

 rpHE publication under review is the last of a series of Annual 

 JL Reports which we owe to Arthur L. Day as Director of the 

 Geophysical Laboratory of the Carnegie Institution. It must be 

 a source of great gratification to Day to realize the high position 

 which the Geophysical Laboratory has won for itself in scientific 

 regard in the course of a comparatively few years. 



The present Annual lleport leaves untold the story of the year's 

 progress achieved in the laboratory, for nothing but war work has 

 been attempted. It gives, however, a most valuable resume of papers 

 written by members of the staff and published in various American 

 scientific journals. These papers, it is explained, are for the most 

 part records of researches in progress at the time of the entry of the 

 United States into the War. 



The summary thus afforded exactly meets the requirements of 

 geologists the world over. It is an easy matter to turn from it to 

 the journal containing the particular paper to which more detailed 

 reference seems desirable. It is to be hoped on this account that the 

 Annual Reports have a wide circulation. 



Thirty-three papers in all are considered. Several are concerned 

 with laboratory technique. A few, again, relate to matters of pre- 

 dominantly physical or chemical interest, as, for instance, the Planck 

 radiation law, the place of manganese in the Periodic Table judged 



