The supply of numbers one and two of this JOURNAL remaining in the hands of the publishers has become reduced below the limit they desire to preserve for binding and for special purposes, and they would esteem it a great favor on the part of those who may have received duplicates, as sample copies or by the accidents of mailing while the lists were imperfect, if they would return such duplicates to them. They will gladly return the postage if the address of the sender is placed on the wrapper. _REVIEWS._ CRYSTALLINE ROCKS FROM THE ANDES. _Untersuchungen an altkrystallinen Schiefergesteinen aus dem Gebiete der argentinischen Republik_ von B. KÜHN. Neues Jahrbuch für Min., etc., Beit. Bd. VII., 1891, p. 295. _Untersuchung argentinischer Pegmatite, etc._, von P. SABERSKY, _ib._ p. 359. _Untersuchungen an argentinischen Graniten, etc._, von J. ROMBERG, _ib._, VIII., 1892, p. 275. Travelers and foreign residents in South America are rapidly furnishing information relative, not only to the volcanic, but also to the older crystalline rocks composing the great Andes chain. Since the early observations of Darwin,[54] the petrographical collections made by Stelzner during his three years’ residence, as professor, at Cordova (1873–1876) have been described by himself[55] and Franke,[56] while the results of detailed studies of the more extensive collections gathered by Stelzner’s successor, Professor L. Brackebusch, are now beginning to appear. Professor Brackebusch’s residence in the Argentine Republic lasted from 1876 till 1883, and during this period he made numerous scientific expeditions.[57] The petrographical material thus obtained has been confided to specialists in Germany for study. Three papers dealing with the crystalline schists (gneisses),[58] pegmatites,[59] and granites,[60] have recently appeared. The rocks of the granite contact-zones had been placed in Professor Lessen’s hands before his death, while communications on other special groups are doubtless to be expected. These investigations naturally suffer from the forced absence of all field observations on the part of their authors, but the purely petrographical study of the material brings to light many points of interest, while it furnishes the only sort of detailed information regarding the rocks of these remote regions which we can for the present hope for. It is here desired only to direct attention to a few of the most striking results obtained from the Brackebusch material by the three authors last cited.