Geology and Mineralogy, 397 



Separate analyses of the mineral components are also given. To 

 this rock of the syenite family composed almost solely of soda- 

 bearing constituents, the author gives the name of Mariupolite. 



L. V. p. 



11. Dahamit, ein neties Ganggestein aiis der Gefolgschaft des 

 Alkaligranit ; von A. Pelikan. (Denkschriften der mat. -n at. 

 wiss. classe der K. Akad. der. Wiss. Wien, 1902. Bd. Ixxi.) — In 

 an article dealing with the petrography of a rock collection from 

 the islands of Socotra, Abd el Kuri and Semha the author de- 

 scribes a dike rock of a chocolate brown color, compact texture, 

 containing red phenocrysts of thin tabular feldspar. The micro- 

 scopic study and the chemical analysis shows the rock to consist of 

 6-8 per cent riebeckite, 43-8 per cent albite, 2-8 per cent anorthite, 

 12 -2 orthoclase, 31 "5 per cent quartz. The chemical analysis by 

 E. Ludwig gave 



SiOa AI2O3 FesOs FeO MgO CaO Na20 KsO H2O Sum. 

 74-02 13-56 1-93 1-09 0-23 0-56 5-80 2-06 1-05 == 100-30 



The phenocrysts are albite or albite-oligoclase, containing the 

 small amount of anorthite. The other components are mixed in 

 the groundmass. The author suggests the name from the locality, 

 Dahamis, and offers the fact that it differs from grorudite (quartz 

 tinguaite) in containing riebeckite instead of aegirite, as a reason 

 for the new name. He overlooks entirel}^ however, the fact that 

 Osann (Tscher. Min. Mitt., vol 15, p. 435, 1895) has already 

 described a dike rock consisting of alkali feldspars, quartz and 

 riebeckite under the name of paisanite, the analysis of which also 

 agrees in essential particulars with that above. The rock should 

 be regarded as a variety of paisanite. l. v. p. 



12. Mineral Resources of iSoutli Dakota ; by C. C. O'Harra 

 and J, E. Todd. South Dakota Geol. Survey Bull. No. 3, pp. 

 130 ; pi. 31. — The mineral wealth of the Black Hills has already 

 been described by Professor O'Harra (this Journal, vol. xiii, p. 

 474). Professor Todd, State Geologist, gives a report (pp. 81- 

 130) on the mineral Building Materials, Fuels and Waters of 

 South Dakota. 



13. Note on a neio occurrence of Native Arsenic ; by Nevil 

 Norton Evans. (Communicated.) — During the past summer 

 native arsenic was discovered in a calcite vein cutting the nephe- 

 line syenite at Montreal, Canada, by Mr. Edward Ardley, Museum 

 Assistant at the Peter Redpath Museum, McGill University. The 

 mineral appears to be pure arsenic, not more than traces of other 

 elements having as yet been found in it. The vein has a maxi- 

 mum thickness, so far as has been seen, of two inches, and has 

 already yielded about fifty pounds of the arsenic. A complete 

 analysis, together with a detailed study of the occurrence, is 

 being made by the writer, and will be published shortly. 



McGill University, Montreal. 



14. The Inverness Earthquake of September 18th, 1901, and 

 the Carlisle Earthquake of July, 1901 ; by C. Davison. Quart. 



