PETROGRAPHY. 347 



Fi:axt/kx, W. ITatcrsnohuiigcn iihcr (lie (Miedermij;' des iinteroiv MiisclK'lkalks in 

 eiiieiu Tlieilt; voii Tbiiriugeii uiul Hosscii mid iiber dio Nattir der Oolitlikih-uor in 

 dieseu Gebirgssciiichtcii. Jubrb. der k. prous. gcol. Landiuid Bergiika<U'iiiie zu 

 Beiiiu, 1887, p. 1. Tbrco full-page phites sbowing uiicro-.strnctnres. 



FniEDEi,, C. Sur un giscniont do diauumts at do sapbirs <1' Aiistiaru'. UiiU. Soc. 

 Franoaiw! Miiieralogio, Fiibniary, 1888, vol. XI, p. (it. 



(Jkiuiaki), Ai.i"Ki;i) lOixivii. IJoitiag zur Koniitiikss dor sogcnannlcn •• Sodagianitc" 

 Iiiaugiiral-Disseitalion. Jjoipzig, 1887, tliirty-bvo pages. 



Gill, A. C. Pot.rograpbioal nofcos on a Rock Collection iVoni I'ci nando .Xoronlia. A 

 preliminary notice. Jobns Hopkins Univ. Circular, April, IriSS, j). 71. 



GOKGKN, Alkx. Sur la production artiliciellede la /incite et do la Wilicuiite. Ibill. 

 Soc. Franvaiso Mineralogio, January, 1887, vol. .\, p. ;5(!. 



GoTZ, .1. Uobor Andalu.sit aus den krystallinon .Scbicifern von Marabastad, Trans- 

 vaal. Nouo.s.Iabrb., 1887, i. Band, zwoitos Heft, ]). 211. 



GiiAKi-'K, Fka.nz Vii. Min(!ralogiscb-j)etrograi)bis(die llntersiudiung von Eliiolitbsy- 

 eniten von der Serra de Tingua, Provin/, liiocbs .lauoiro, Brasilien. Noues Jabrb. 

 Mill., Geol., etc., 1887, ii, Baud, p. 222. 



Describes tbo micro-structures and mineral composition of tlie nepboline-bcar- 

 iug rocks of Brazil, tbo bold relations of wbi(di wen; described by O. A. Derby 

 in Quar. Jour. Geo]. Soc. for August, 1887. 



Laaveuit im brasilianiscbeu Elaeolitiisyenit. Neiies Jabrb. Min., (jooI., etc., 



1887, zweites Heft, p. 201. 



Gkatacap, L. p. Tbe Eozoonal Rock of Maiibattan Island. Am. .Jour. Sci., I'.d, 



1887, vol. x.xxiii, pp. :i74-:i78. 



Describes tbe serpentine as secondary after a mineral of tbe ampbibole group. 



Grksley, W. .S. Notes ou Cone in Cone. Geol. Mag., .January, 1887, \). 17. 



GuRIcii, G. Beitrjige zur Geologie von West-Afrika. Zeitscbrift d<!r deut. geol. 

 Gesell., January, 1887, xxxix. B., 1. Heft, p. IHi. 



Deseribea foyaits from tbe Isle de Los and from Tuml)o. Tbese all carry 

 ortboclaso, ebeolite, bornblondt^, aud maguotite, while more or less sporadically 

 occur sodalite, cancrinite, augite, a-gerine, lavenite, astropbyllite, zircon, and 

 speue. Other rocks descril)ed are an olivine gabbro from Freetown, diabase and 

 diorito, oliviue diabase, araphibolite, saTjdstoue, aud gneiss from various points. 



Gyllixg, H.ialmar. Zur Geologie dor cambri.scheu Arkosen-Ablagerung des west- 

 licbeu I'Mulaud. Zeitscbrift deuts. gool. Gesell., 4. Heft, x.vxix, p. 770. 



H.\KKEK, Aleued. Additional note ou the Blue Ilornbleude of Myudd Mawr. Geol. 

 .Mag., October, 18,-8, p. A'k). 



Calls attention to tbo piobability of a blue hornblende found in the (piartz 

 pori>hyry proving to be riebeckite. 



Woodwardiau Museum notes on some Anglesey Dykes. Geol. Mag., June;, 



1888, p. 2t)7. 



On tbe Eruptive Kocks in tbe neighborhood of 8arn, (Jaeinarvonsbire, C^uar. 



.Jour. Geol. Soc, No. llTy, August, 1888, vol. xi,i\ , p. 442. 



Describes tbo rocks of the area as (1) granites and granitic gneiss, (2) gabbro 

 diorito and gneissic diorite, (IJ) diabase, (4) borubloudo diabase, (5) horubleudo 

 picrite, and (6) dolerite. 

 Haktlev, W. N. The Black Marbles of ICilkenuy. .'■ci.Proc. l\oy. Dub. Soc, April, 

 1887, vol. V, p. 480. 



Gives results of chemical analyses. 

 Hatch, Fueuekick H. On the spheroid-bearing Granite of Mullaghderg, County 

 Douegal. Quar. .Jour. Geol. Soc, No. 175, August, 1888, vol,XLi\', p. 548. 



Describes the spheroids as compo.sed of a nucleus of oligoclase, biotite, and 

 over 12 per cent, magnetite with a peripheral shell of radiating feldspars, chielly 

 oligoclase. a little (juartz, and jiossibly ortboclaso. Size of spheroids about :? by 4 

 inches. The granite itself is described as a " sphene-beariug horublendo gran- 

 ite." 



