August?, 1896.] 



SCIENCE. 



163 



CURRENT NOTES ON PHYSIOGRAPHY. 

 HILLS AND PLAINS OF SOUTHEAST LOUISIANA. 



The state Experiment Station at Baton 

 Eouge has just issued a report on the 

 Florida parishes of east Louisiana and the 

 bhiff, prairie and hill lands of southwest 

 Louisiana, by W. W. Clendenin, of the 

 State University, with a lucid account of 

 the topography and drainage. East of 

 Baton Rouge the ' pine hills ' grade west- 

 ward into the ' bluff ' district toward the 

 Mississippi, and southward into the ' pine 

 flats ' toward the sea marsh. The ' pine 

 hills ' have a mature topography, produced 

 by pre-Columbian dissection of Lafayette 

 strata, and now thinly veneered by the 

 loam of Columbian submergence. The 

 streams still occupy their pre-Columbian 

 courses, giving typical examples of resur- 

 rected drainage. Passing towards the Mis- 

 sissippi the veneer of Columbia thickens ; 

 the pre-Columbian topography fades away, 

 and at last disappears beneath the flat cover 

 of ' bluff' or loess. Here the topography is 

 adolescent; extensive interstream plains 

 still standing between narrow, steep- sided 

 valleys. The ' pine flats ' are an infantile 

 coastal plain of Columbia clays, so level that 

 the rainfall is hardly gathered into streams ; 

 the larger water courses seeming to be the 

 seaward extensions of the resurrected 

 streams from the ' pine hills.' 



PIMPLED PRAIRIES OF SOUTHWEST LOUISIANA. 



The same report describes the coastal 

 prairies of southwest Louisiana, upon which 

 there are numerous mounds, especially 

 around the sulphur district of Calcasieu 

 parish, but extending also inland to the 

 ' pine hills ' and seaward to the coastal 

 marsh. The mounds are roughly circular 

 in outline, about fifty feet in diameter and 

 up to ten feet in height ; always arranged 

 in zones or intersecting systems of lines, 

 never solitary. They are more sandy than 

 the argillaceous prairie, and hence are drier 



and support trees and a better pasture grass 

 than that of the marshy plain. Clendeniu 

 discards Hilgard's explanation of the mounds 

 as ant hills, and follows Hopkins in compar- 

 ing them to ' mud lumps,' formed by the es- 

 cape of gas from beneath ; adding that the 

 zonal and linear arrangement of the mounds 

 may be accounted for by associating them 

 with the radial and branching fractures 

 that diverge from earthshock centers. Ac- 

 cording to this theory, ants, like plants, oc- 

 cupy the mounds but do not make them. 



Lubbock's scenery of Switzerland. 

 This admirable book (Macmillan, 1896) 

 shows how thoroughly a sagacious amateur 

 may follow, appreciate and transmit to a 

 large circle of readers the best physiographic 

 results gained by geologists and geographers 

 of Switzerland. The many essays and 

 memoirs quoted appear to have been inter- 

 preted, and indeed verified on the ground, 

 during the authors' vacations during the 

 past thirty years. Beginning with geo- 

 logical structure, chapters follow on glaciers 

 present and past, rivers, valleys, lakes, in- 

 fluence of strata on form, the Jura, the 

 central plain, the outer Alps and the central 

 massives ; then come ten other chapters on 

 districts of particular interest, such as Lake 

 Geneva, Mont Blanc, the Rhine, the Reuss. 

 etc., closing with a general summary. 

 There is no book in English in which 

 so compact and accurate an account of 

 the physiography of Switzerland is to be 

 found. It is on every account to be most 

 warmly w^elcomed and commended to stu- 

 dents, travelling or at home. The contests 

 and exchanges between the several branch- 

 es of the upper Rhine are well presented, 

 after Heim ; but the processes by which a 

 river may come to follow an anticlinal axis, 

 and the many ways in which rivers may 

 come to cross mountain ridges, are not fully 

 appreciated. The delta-like origin of the 

 Rigi conglomerates, now overturned ; the 



