GEOLOGY OF THE WESTERN ALPS. 173 



indicate that the author has ever read any work not written 

 in Italian. 



When, therefore, both the premises and the methods of 

 argument are so different, it is not surprising that the 

 conclusions are as diverse as they can be, and that the use 

 of the tools of 1830 lead us back to the theories of that 

 period. 



Under these circumstances immediate agreement is 

 hopeless. We can only trust that by the patient accumu- 

 lation of facts ; by the abandonment of the construction of 

 maps of complex Alpine regions from traverses along the 

 coach roads, and the effort to unravel difficult igneous 

 series without previous training in simpler volcanic areas 

 elsewhere ; and by the constant use of the microscope 

 to detect the differences between rocks which superficially 

 appear alike, the basis of an agreement may be at last 

 attained. 



BIBLIOGRAPHY. 



(1) ROTHPLETZ, A. Geotektonische Probleme, 175 pp., 107 figs., 



and 10 plates of sections. Stuttgart: 1894. 



(2) SCHARDT, HANS. Sur 1' origine des Prealpes Romandes 



(Zone du Chablais et du Stockhorn). ArcJi. Sci. Phsiq. 

 Nat. Geneve, ser. 3, t. xxx., No. 12, pp. 570-583, Dec, 1893. 

 The views of this paper are repeated by the author in 

 Livret Guide Geologique dans le Jura et- les A /pes de la 

 Suisse, pp. 171-195, pi. x. Lausanne: 1894. 



(3) SARASIN, Ch. De 1' origine des roches exotiques du flysch. 



Arch. Sci. Phsiq. Nat. Geneve, ser. 3, t. xxxi., pp. 570-603, 

 June, 1894; t. xxxii., pp. 67-101, July, 1894. 



(4) Haug, E. L' Origine des Prealpes Romandes et les Zones 



de Sedimentation des Alpes de Suisse et de Savoie. Ibid., 

 ser. 3, t. xxxii., No. 8, pp. 154-173, 1894. 



(5) BONNEV, T. G. Mesozoic Rocks and Crystalline Schists in 



the Lepontine Alps. Quart. Jouru. Geo/. Soc, vol. 1., pp. 

 285-302, 1894. 



(6) Bertrand, Marcel. Etudes dans les Alpes Franchises. 



Structure en eventail. Massifs amygdaloides et Meta- 

 morphisme. Bull. Soc. Geol. France, ser. 3, t. xxii., pp. 

 69-118, pis. iv., v., vi., 1894. Schistes lustres de la zone 

 centrale. Ibid., pp. 1 19-162, pi. vii. 



