Of more recent works we must especially notice those of the engineers of the Direccion de Minas:-- R. Stappenbeck y F. Reichert, "Informe preliminar relativo a la parte sudeste del Territorio del Chubut" (_An. Min. Agric._, Seccion Geol. Mineral., y Minas, vol. ix, No. 1, Buenos Aires, 1909). Ricardo Wichmann, various studies of the eastern part of the plateau of the Rio Negro (_ibid._, xiii, Nos. 1, 3 and 4, Buenos Aires, 1918 and 1919). A. Windhausen, studies on the Rio Negro and the Neuquen (_ibid._, x, No. 1, Buenos Aires, 1914). The geological results of Windhausen's work are summarized in articles that appeared in the _American Journal of Science_ (4th series, xlv, 1918, pp. 1-53) and in the _Bol. Acad. Nac. Ciencias Cordoba_ (xxiii, 1918, pp. 97-128 and 319-364). We must add G. Rivereto, "La valle del Rio Negro" (_Bol. Soc. Geologica Ital._, xxxi, 1912, pp. 181-237, and xxxii, 1913, pp. 101-142). _B. The Andes._ Numerous articles in the _Bol. Inst. Geog. Argent._ and the _An. Soc. Cient. Argentina_, immediately after the military expedition of 1879-1880 (Host, Ave-Lallemant, etc.). A detailed study of the Andean region was undertaken at the time of the frontier-quarrel between Argentina and Chile, and this led to a number of publications. The work done by the Argentinians under F. P. Moreno is used in _Frontera Argentina-Chilena, Memoria presentada al tribunal nombrado por el Gobernio de su Majestad Britanica_ (London, 1902, 2 vols. quarto, 1 vol. maps, and 1 vol. photographs), and in the _Breve Replica a la memoria Chilena_ (London, 1 vol. quarto, 1902). See a summary of the results in L. Gallois, "Les Andes de Patagonie" (_Annales de Geographie_, x, 1901, pp. 232-259). In the _Revista_ and the _Anales_ of the La Plata Museum will be found part of the research made during this period (1897-1900) by Argentine experts; especially the work of Burckhardt and Wehrli on the Neuquen Cordillera. The Chilean work which served as the basis of the _Statement presented on behalf of Chile in reply to the Argentine Report_ (London, 1902, 4 vols. and 2 vols. as appendices) is, on the whole, less valuable. Of later travellers we must mention P. D. Quensel, "On the influence of the Ice Age on the continental watershed of Patagonia" (_Bull. Geol. Inst. Univ. Upsala_, ix, 1908-9, pp. 60-92), and "Geologisch-petrographische studien in der Patagonischen Cordillera" (_ibid._, xi, 1912, pp. 1-114). Very important surveys in the Cordillera and on the plateau of the Rio Negro were made under the direction of Bailey Willis (_Northern Patagonia_, Ministry of Public Works, Bureau of Railways, Argentine Republic; text and maps by the Comision de Estudios hidrologicos, Bailey Willis Director, 1911-1914, New York, 1914, 1 vol and atlas).