ology cmd Mineralogy, 69 



glancophane, eoisite, saussurite, feldspars even in the half-altered 



sandstones, of which oligoclase, labradorite, and orthoclase are 



irring kinds, the first of the three most common, the last, rare; 



also epidote, garnet, chlorites, serpentine, rutile, titanite, zircon, 



apatite. The rocks include diabase, dioryte, (for which meta- 

 morphic kinds the author proposes the term pseudodiabctAe, pseudo- 

 diorite, overlooking the terms metadiabase, metadioryte, proposed 



in 1876, and used in this Journal in a paper by Mr. G. \Y. 

 Hawes) ; coarsely crystalline forms of the diabase or gabbro, 

 with zoisitic and hornblendic varieties ; glancophane schists, 

 containing quartz, a soda feldspar, usually some zoisite and mica, 

 often garnets, passing into gneiss-like varieties on one side and 

 into thin-schistose on the other, and, at Mt. Diablo exhibiting a 

 distinct passage from shales to the schist, proving, as Mr. Becker 

 Bays, that -the schistose structure is an original feature, not a 

 result of raetamorphism" ; phthanyte, or flinty silicified sand- 

 stones or shales ; serpentine. The serpentine is found to have 

 been produced through an alteration of the sandstones, all the 

 kinds having undergone the change ; and the minerals altered to 

 serpentine include augite, hornblende, feldspar, chlorite, garnet, 

 and even quartz and apatite. Mr. Becker discusses the conditions 

 of these and other metamorphic changes, and throws much light 

 upon the question of origin. 



From the part of the work on quicksilver deposits much might 

 be here cited which is of prominent geological importance. The 

 discussion of the origin of the deposits leads also to observations 

 on the origin of metallic deposits of other kinds. The author had 

 visited the mines of Europe before writing his report. The atlas 

 contains geological maps of differing mining regions, and also 

 diagrams of mine-workings, mine-sections, and other matters of 

 economical interest. 



4. A new locality of Lower Silurian Fossils in the Limestones 

 of Columbia Co., N. Y. ; by I. P. Bishop. (Communicated 

 by the author).— In October, 1887, I found near Pulver's Station, 

 about 2\ m\les north of Philmont, Columbia Co., K Y., and with- 

 in territory heretofore considered as Taconic, an outcrop of lime- 

 stone. A very brief search revealed unmistakable organic re- 

 mains, among which were several gasteropods, crinoid stems and 

 a cast of a single brachiopod valve. A few clays later I visited 

 the spot again and brought away several specimens, only one of 

 which, a Multiculopora, could be identified. More urgent duties 

 prevented any further search for fossils that season ; but in the 

 spring and summer of 1888, I visited the place several times and 

 made a careful examination of about one-third of the whole out- 

 crop. The organic remains proved to be not only more abundant 

 than in the other fossiliferous localities previously discovered,* 

 but to be in*greater variety and in a better state of preservation. 

 As many as six or seven Orthocerata were plainly distin- 

 guished ; but owing to the massive character of the limestone, I 



* Vide this Journal, vol. xxxii. p. 438, 1886. 



