PETROGRAPHY. 347 



Frantzen, W. Uatersnclinu<5en iiber die, (Tliederniig des unteren Muschelkalks in 



eiuem Tlieile von Thiiiiujren uiid Hessou und iiber die Natnr der Oolithkoruer in 



diesen Gebirgsscliichtoii. Juhrb. der k. prens. geol. Laud-nnd Bergakadeiiiie zu 



Berlin, 1887, p. 1. Three full-page plates showing niicro-strnctnres. 



Frikdel, C. Sur un gisemeut de diaiuants et de sapliir.s d' Anstralie. Bull. Soc. 



Franc^-aise Miueralogie, February, 1888, vol. xi, p. (54. 

 Gkrhakd, Alfkko EixiAU. Beitrag zur Kenutniss der sogeuannteii '' Sodagranite." 



luangnral-Disseitation. Leipzig, 1887, thirty-five pages. 

 Glix, A.. C. Petrograpliical notes on a Rock Collection from Fernando Noronha. A 



preliminary notice. Johns Hopkins Univ. Circular, April, 1888, p. 71. 

 GoRGEN, Alex. Sur la production artificiellede la zincite et de la Willemite. Bull. 



Soc. Fran^aise Mineralogie, January, 1887, vol. X, p. 36. 

 G<")TZ, J. Ueber Andalusit aus den krystalliuen Schiefern von Marabastad, Trans- 

 vaal. Neues Jahrb., 1887, i. Band, zweites Heft, p. 211. 

 Grakfk, Franz Fr. Mineralogisch-petrographische Untersncliung von Elliolitlisy- 

 eniten von der Serra de Tingua, Provinz Rio de .Janeiro, Brasilien. \eues Jahrl>. 

 Min., Geo!., etc., 1887, ii, Band, p. '222. 



Describes the micro-structures and mineral composition of the nepheliue-bear- 

 . lug rocks of Brazil, the field relations of which were described by O. A. Derby 

 in Quar. Jour. Geol. Soc. for Auiiust, 1887. 



Laaveuit im brasiliauischen Elaeolithsyenit. Neues Jalirb. Min., Geol., etc., 



1887, zweites Heft, p. 2Ul. 

 Gratacap, L. p. The Eozooual Rock of Manhattan Island. Am. Jour. Sci., M, 

 1887, vol. XXXIII, pp. .374-378. 

 Describes the serpentine as secondary after a mineral of the amphibole group. 

 Gresley, W. S. Notes on Cone in Cone. Geol. Mag., January, 1887, p. 17. 

 Gurich, G. Beitriige zur Geologie von West-Afrika. Zeitschrift der dent. geol. 

 Gesell., January, 1887, xxxix. B., 1. Heft, p. 1)6. 



Describes foyaits from the Isle de Los and from Tumbo. These all carry 

 orthoclase, eheolite, liornbleude, and magnetite, while more or less sporadically 

 occur sodalite, caccrinite, augite, a'gerine, lavenite, astrophyllite, zircon, and 

 spene. Other rocks described are an olivine gabbro from Freetown, diabase and 

 diorite, olivine diabase, ainphibolite, sandstone, and gneiss from various points. 

 Gylling, Hjalmar. Zur Geologie der cambrischen Arkosen-Ablagerung des west- 

 lichen Finland. Zeitschrift dents, geol. Gesell., 4. Heft, xxxix, j). 770. 

 Harker, Alfred. Additional note on the Bine Hornblende of Myndd Mawr. Geol. 

 Mag., October, 18-8, p. i^yb. 



Calls attention to the probability of a blue hornblende found in the quartz 

 pori)hyry proving to be riebeckite. 



Woodwardian Museum notes on some Anglesey Dykes. Geol. Mag., Juno, 



1888, p. 207. 



On the Eruptive Kocks in the neighborhood of Sam, Caernarvonshire, Quar. 



Jour. Geol. Soc, No. 175, August, 1888, vol. xliv, p. 442. 



Describes the rocks of the area as (1) granites and granitic gneiss, (2) gablu-o 

 diorite and gneissic diorite, (3) diabase, (4) hornblende diabase, (5) hornblende 

 picrite, and (6) dolerite. 

 Hartley, W. N. The Black Marbles of Kilkenny. .'■ ci. Proc. Roy. Dub. Soe., April, 

 1887, vol. V, p. 486. 

 Gives results of chemical analyses. 

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

 Donegal. Quar. Jonr. Geol. Soc, No. 175, August, 1888, vol. xliv, p. 54f^. 



Describes the splieroids as c()mi)osed of a nucleus of oligoclase, biotite, and 

 over 12 per cent, magnetite with a peripheral shell of raduiting feldspars, chieHy 

 oligoclase. a little (piartz, and possibly orthoclase. Size of spheroids about 3 by 4 

 inches. The granite itself is described as a " sphene-bearing hornblende graa- 

 ite." 



