672 



SCIENCE. 



[N. S. Vol. XI. No. 278. 



Irrigation Papers, U. S. Geol. Surv., No. 32, 

 1899). 



THE DUNES OF GASCONY. 



The great belt of dunes that borders the 

 straight coast of Gascony is well described by 

 E. Le Mang (Deutsch geogr. Blatter, Bremen, 

 xxii, 1899, 235-256). The dunes frequently 

 rise 40 meters (one reaches 89 m.) over a belt 6 

 or 8 kil. wide and 240 kil. long. Near the sea 

 the ridges lie north and south, parallel to the 

 shore ; further inland they trend east and west, 

 parallel to the prevailing winds. The inland 

 dunes have long been forested and stationary ; 

 the shore dunes were until recently barren and 

 wandering. Fields and forests were buried and 

 villages were overwhelmed by the advancing 

 sand ; the mouths of streams were blocked and 

 shifted ; lagoons were pushed inland with ris- 

 ing water level, invading and drowning fields 

 and villages. Nov/, after many years of ex- 

 perimental effort and nearly a century of sys- 

 tematic work, the advancing dunes have been 

 arrested. A half artificial dune or dike runs 

 along the beach, with very gentle slope to the 

 sea ; here the wear of winter storms must be 

 repaired during the succeeding summer. Next 

 follows a protection zone, 300 to 1500 met., 

 wide, covered with stunted firs and bushes, 

 where the first strength of the sea wind is ex- 

 pended. Then comes the great artificial forest 

 of firs and oaks, under whose cover the in- 

 vasion of the dunes has entirely ceased. 



THE MORVAN. 



An ai'ea of crystalline rocks, forming an up- 

 land known as the Morvan, a northern branch 

 of the central plateau of France, was visited in 

 the spring of 1899 by a party under the direc- 

 tion of M. V61ain, professor of physical geog- 

 raphy at the Sorbonne ; and a report of the 

 excursion is made by M. Martoune, instructor 

 in geography in the university of Rennes (An- 

 nales de Geogr., viii, 1899, 405-426, maps and 

 photos.). The mesozoic strata that once cov- 

 ered the crystallines of this district more or less 

 completely are now worn back so that the an- 

 cient crystalline floor is broadly revealed as a 

 plateau, gently undulating where it has longer 

 been exposed to erosion, remarkably even where 

 recently uncovered; the harder members of the 



overlapping strata have retreated in strong es- 

 carpments that rim around the crystalline area, 

 on the east, north and west, while the less re- 

 sistant members are reduced to plains between 

 the scarped reliefs. A recent general elevation 

 is iudicated by the narrow valleys, frequently 

 having incised meanders, by which the uplands 

 and lowlands are alike dissected. The origin 

 of the drainage is not especially considered ; it 

 appears to be in greater part the accordant 

 with the general dip of the strata away from 

 the Morvan center, and hence would be classed 

 as originally consequent. 



THE FLAMING. 



Between the mountains of middle Germany — 

 Harz, Erzgebirge, Riesengebirge — on the south, 

 and the Baltic lowlands on the north runs a belt 

 of low uplands, underlain by some inequality of 

 rock-floor and built up as a ' diluvial plateau ' 

 by the moraine of an early glacial epoch ; 

 now cut into disconnected parts by the broad 

 valleys of glacial rivers. The Flaming is one 

 of these uplands, lying east of Magdeburg be- 

 tween the Elbe and the Spree. It is recently 

 described by E. Schone (Beitr. zur Geogr. mittl. 

 Deutschland, herausg. von F. Ratzel. Wiss. 

 Veroffentlichungen Verein f. Erdkunde, Leip- 

 zig, iv, 1899, 93-194). The softly rounded 

 hills are separated by ramifying dry valleys or 

 'Rummeln' which lead streams in wet weather. 

 Faint terraces on the sloping valley sides are 

 ascribed to stream action during the erosion of 

 the valleys, although in a photographic illus- 

 tration they closely resemble pasture paths, and 

 indeed their modification by sheep is noted in 

 the text. The steeper valleys on the northern 

 slope of the Flaming have supplied gravel for 

 the construction of a number of flat alluvial 

 fans on the floor of the bordering glacial river 

 trough. 



W. M. Davis. 



BOTANICAL NOTES. 



FOSSIL PLANTS OF THE BLACK HILLS. 



A RECENT paper in the nineteenth annual 

 report of the United States Geological Sur- 

 vey, entitled ' The Cretaceous Formation of the 

 Black Hills as indicated by the Fossil Plants,' 

 by Lester F. Ward, is of more than usual in- 



