PETROGRAPHY. 339 



that andahisite, a mineral considered as normally a product of con- 

 tact metamorpliisiu in the crystalline schists, is in microscopic forms 

 a by no means rare constituent of the true granites. Williams * de- 

 scribes for the first time in this country the presence of pleonast (her- 

 cynite) as occurring in the norites of the Hudson River region, Xew 

 York, and also perowskite as a microscopic constituent of the altered 

 l)eridotite at Syracuse, in the same State. A more interesting discov- 

 ery than any of the above is that of the occurrence of leucite, hitherto 

 found only in recent lavas, in some paleozoic eruptions of Brazil, as an- 

 nounced by Derby.t Schmidt has noted for the first time the altera- 

 tion of olivine in a melaphyr from the Swiss Alps into a bastitelike 

 substance. Williams | has noted the occurrence of rutile secondary 

 after ihnenite in a decomposed diabase from the Big Quinnesec Falls 

 of the Menominee River, Wisconsin. That, however, these are in fact 

 alteration products Cathrein denies. § This last-named authority has 

 also described || an interesting case of the occurrence of plagioclase 

 pseudomorphous after garnets in a garnet amphibolite from the Swiss 

 Alps. The mineral cordierite, as an essential constituent of rock 

 masses, has for the first time in America been observed by Hovey^ in 

 a gneiss occurring near Guilford, Connecticut. 



The secondary" enlargement of the mineral particles of fragmental 

 rocks as described by Tiirnebolim, Sorby, Irving, and Van Hise, has be- 

 come a matter of almost daily observation. Such growths are not, 

 however, confined to clastic rocks. Becke has described a case of sec- 

 ondary enlargements of the hornblende in massive eruptive rocks, and 

 Van Rise ** has described a like secondary grov,th of hornblende upon 

 both hornblende and augites in certain Wisconsin diabases. Lastly, 

 the present writer has described tt a case of the secondary enlargement 

 of augites by fresh deposition of augitic material in a peridotite from 

 Little Deer Isle, on the coast of Maine. 



NECROLOGY. 



The science has suffered greatly through the deaths of Ur. Max 

 Schuster, of the (Tuiversity of Vienna; of I'rof. R. D. Irving, U. S. 

 Geological Survey, Madison, Wisconsin ; of Prof. H. Carvill Lewis, 

 Philadelphia, Pennsylvania., and Dr. Theodor Kjerulf, of Christiania, 

 Korwav. 



*Neues Jahrb., 1887, n B., p. 267. 

 tQiiiir. Jonr. Geo!. Soc, 1887, Vol. xi.ui. No. 171. 

 t Nones J:ibib., 1887, ii B., p. 263. 

 vS Ibid., 1888, II B., 2 Heft, p. 151. 

 Wllnd., 1887, iB., 2 H., p. 147. 

 H Am. Jour. Sci., July, 1888, j). 57. 

 ""Ibid., May, 1887, p. 385. 

 tt/6irf., June, 1888, p. 488; also Proc. U. 8. Nat. Mus., 1888, p. U)l, 



