Geology and Mineralogy. 391 



somewhat unfair decision where tbe case was one of unprovoked 

 attack, and this based on material published by Dr. Carpeuter 

 and myself." By referring to Dr. Dawson's article in this Jour- 

 nal for 1879 (vol. xvii) the reader will be able to judge whether 

 Professor Mobius's article six months later (vol. xviii) was an 

 iinprovoked " attack " or not. It appears to us that the " attack " 

 was first made by Dr. Dawson, if there was any "attack" in the 

 discussion. But we did not regard either paper as an " attack," 

 for each was courteous though earnest. We hold that an honest, 

 courteous criticism is not an attack. It is bad for science that 

 investigators should ever thus regard • it ; for in that case criti- 

 cism pretty surely degenerates into attacks which treat oppo- 

 nents as " adversaries." 



5. Nya anmarkningar om Williamsonia of A. G. Nathorst — 

 (Ofversigt af Kongl. Vetenskaps- Akademiens Forhandlingar, 

 June, 1888. No. 6.) — The discovery described in this preliminary 

 note in Swedish is of the highest interest to geologists and 

 paleontologists. It is nothing less than that the author has found 

 the peculiar inflorescence known as Williamsonia angustifo- 

 lia Xath. attached to the stems and foliage of Anomozamites 

 minor (Brongn.) Nath., so as not only to show that the genus 

 Williamsonia belongs to the Cycadacere, as long ago conjectured 

 by Williamson, but also to indicate in what manner these flowers 

 were developed in the forks of the sympodial stems of those 

 cycadean plants. A figure is given showing all this, which, how- 

 ever, is admitted to be largely a restoration, and leaves many 

 things to be explained in the forthcoming memoir which is 

 promised. l. f. w. 



6. Rlebeckite^ a new mineral. — Dr. A. Sauer has described 

 under this name what he regards as a new member of the 

 amphibole family corresponding to segirite among the pyroxenes. 

 It occurs in the granite of the island of Socotra, where it was 

 collected by Dr. E. Riebeck. It appears in slender prismatic crys- 

 tals, black in color, and showing the characteristic cleavage of 

 amphibole. An analysis, after the deduction of 7*12 per cent 

 zircon, yielded : 



Si0 2 Fe 2 3 FeO MnO CaO MgO Na 2 K 2 

 50-01 28-30 9-87 0-63 1-32 0-34 8-79 0-72 = 99-98 



It thus in composition corresponds closely to aegirite and differs 

 from the arfvedsonite analyzed by Lorenzen chiefly in the state 

 of oxidation of the iron ; he found in the Greenland mineral 3*80 

 p. c. Fe 2 3 and 33*43 p. c. FeO. The doubt existing as to the 

 true composition of arfvedsonite, however, prevents a definite 

 conclusion as to the relations of the new mineral to it. — Zeitschr. 

 Geol. Ges., xl, 3 38, 1888. 



7. Mazapilite, a neio mineral. — Dr. G. A. Konig announces a 

 new mineral from Zacatecas, mining district of Mazapil, Mexico. 

 It occurs in deep red to black crystals, believed to be ortho- 

 rhombic. The hardness is nearly 7, the specific gravity 3*567. 

 Preliminary trials have led to the conclusion that in composition 



