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SCIENCE 



[N. S. Vol. XXVIII. No. 721 



been combined into a single curve representing the 

 progress of volcanic and seismic phenomena dur- 

 ing the average sunspot cycle for the same period. 

 On comparing this curve with the average sun- 

 spot curve, it appears that the minimum of the 

 one coincides exactly with the maxima of the 

 other and vice versa, and that times of increase 

 in the one set of phenomena are times of decrease 

 in the other. The coincidence can not possibly be 

 accidental, for the repeated process of averaging 

 would prevent the two curves from agreeing unless 

 there were a genuine cause of agreement. The 

 remarkable nature of the coincidence suggests 

 that there is some common cause at work, pro- 

 ducing a maximum occurrence of earthquakes and 

 volcanoes upon the earth and a minimum occur- 

 rence of spots on the sun. The data used do not 

 claim to be exhaustive, and the results are ad- 

 vanced as suggestive, rather than conclusive. 



This paper appeared in full in the Popular 

 Science Monthly for June. 



The Volcanoes and Rocks of Pantelleria : Henbt 



S. Washington, New York. 



Pantelleria is entirely volcanic. Its geologic 

 structure has been variously interpreted, and the 

 views of the writer differ in some important re- 

 spects from those of other observers, notably 

 I'oerstner and Bergeat. There is supposed to have 

 been formed first a large volcano, covering prac- 

 tically the whole area and submarine in its first 

 stages. This was composed of rather siliceous 

 soda-trachytes and later green pantellerites. The 

 central and upper parts of this cone disappeared, 

 probably by explosion, in analogy with the history 

 of many other volcanoes, leaving a large central 

 ealdera, surrounded by an encircling somma with 

 steep inner scarps and gentle outer slopes. Within 

 the ealdera arose the cone of the second period, 

 now represented by Montagna Grande, the suromit 

 of which is the culminating point of the island, 

 and Monte Gibele on the southeast. The lava 

 of these is a very uniform soda-trachyte. The 

 crater of Monte Gibele seems to have been the 

 original eruptive center for the joint mass, but 

 later the block of Montagna Grande was sepa- 

 rated from the Gibele cone by a fault, with con- 

 siderable tilting of the fault block. On the west- 

 ern and northern sides of this block there were 

 formed several small parasitic cones, which gave 

 vent to flows of black, glassy pantellerite. These 

 and the trachytic flows of the Gibele volcano 

 nearly filled the whole floor of the original eal- 

 dera, the only portion left uncovered being a 

 small comer at the north, where there is a small 



elliptical lake, which is thus regarded as a resid- 

 ual of the old ealdera floor and not an eruptive 

 center. The next phase of eruptive activity was 

 confined to the northwestern part of the island, 

 and the lavas are entirely feldspar-basalts, form- 

 ing several small cinder cones, with flows of scori- 

 aceous basalt. Eruptive activity on the island 

 proper seems to have ceased, and is now evident 

 only in some fumeroles and hot springs. The 

 rocks show a wide range in chemical composition, 

 but belong to but few distinct types. They are 

 characterized by high soda, giving rise to the 

 presence of abundant soda-microcline, segirite and 

 the triclinic cossyrite among the more salie types, 

 and by the high amoimt of titanium among the 

 basalts. 



Other papers presented and those read by title 

 are as follows: 



Geology of Long Island: W. O. Ceosbt, Massa- 

 chusetts Institute of Technology. 

 Salt Formations of Louisiana: G. D. Habeis, 



Cornell University. 

 Certain Silicified Tertiary Rocks of Arkansas: 



R. Ellswoeth Call, New York City. 

 Recent Advances in our Knowledge of the Mag- 

 netite Bodies at Mineville: James F. Kemp, 

 (By permission of the State Geologist of New 

 York.) 

 Interpretation of the Mineral Constitution of 

 Magnesian Minerals through their Analyses: 

 Alexis A. Julien, Columbia University. 

 Silicified Woods of the Arkansas Tertiary: R. 



Ellswoeth Call, New York City. 

 Dwarf Faunas: Heevet W. Shimee, Massachu- 

 setts Institute of Technology. 

 Structure of the Brachial Support of Camaro- 

 phorella, a Mississippian Meristelloid Brachio- 

 pod: J. E. Hyde, Columbia University. 

 A Revised Classification for the North American 

 Lower Paleozoic: A. W. Geabau, Columbia 

 University. 

 Marginal Glacial Deposits: R. S. Take, Cornell 



University. 

 An Erosion Prollem in Arid Regions: Richaed 



E. Dodge, Teachers College. 

 Notes on Recent Mineral Occurrences: Geoege F. 



KuNZ, New York City. 

 The Gibeon Meteorite and other Recent Acces- 

 sions at the American Museum: Edmund Otis 

 HovET, American Museum of Natural History. 

 Chables p. Beekey, 

 Secretary of Section 



