August 9, 1901.] 



SCIENCE. 



221 



series of meridional faults with downthrow to 

 the east,' and the depression occupied by the 

 lake itself is said to be ' a fault valley.' It is 

 not stated whether these faults, more or less 

 worn, are yet so recent that they dominate the 

 topography, or whether they are ancient favilts 

 produced while yet a heavy series of strata 

 overlay the present surface, and only developed 

 into existing topographic features by erosion 

 long subsequent to faulting. Glacial erosion is 

 regarded as having rounded off the northern 

 slopes of many of the mountains, leaving the 

 southern slopes of greater declivity ; and a few 

 cliflf- walled cirques are ascribed to local glaciers. 

 Lakes are very numerous and are as a rule re- 

 ferred to drift obstruction ; ' there is yet no 

 evidence that any of them occupy rock basins ' 

 (84). The rivers have all developed reaches 

 ('still- waters' or 'levels') on drift, interrupted 

 by rapids on ledges. The drift plain bordering 

 the mountains is well occupied, while the moun- 

 tains are largely a rugged wilderness. 



SLATE MOUNTAINS OF THE MIDDLE RHINE. 



The report of an excursion conducted by Pro- 

 fessors Rein and Philippson over the plateaus 

 and valleys of the middle Rhine (' Wiss. Ausflug, 

 Siebengebirges-Rhein-Eifel-Mosel,' 19-25 Sept., 

 1899 ; Verhandl. VII. Internat. Geogr. Kon- 

 gresses, Berlin, 1900, 328-344) presents some 

 interesting details concerning that attractive re- 

 gion, its physiographic features being described 

 by Philippson. The lofty mountains of Car- 

 boniferous deformation were reduced, partly by 

 subaerial denudation, partly by marine abrasion, 

 to a low torso, afterwards broken into blocks 

 which were irregularly elevated and depressed. 

 The Rhine crossed the region along a depressed 

 block, whose surface it modified, producing a 

 broad trough, which now stands at altitudes of 

 300-350 m. The Mosel eroded a branch trough, 

 whose altitude is now 350-400 m. Pauses in 

 the uplift of the region to its existing position 

 are indicated by terraces, of which the prin- 

 cipal one, strewn with river waste, reaches 

 heights of 200 m. It is in the floor of this ter- 

 race that the narrow gorges of the Rhine and 

 Mosel are cut. Troughs, ten-aces and gorges 

 are the work of Pliocene and later time. Fre- 

 quent mention is made of the extended views 



over the plateau in which the troughs and the 

 deeper valleys have been cut, of the volcanic 

 cones and maare that ornament it, and of the 

 ridges of resistant quartzite that rise over it. 

 Yet it is concluded that the plateau is not a 

 peneplain and that its history is still to be made 

 out. Truly it is not a peneplain, everywhere 

 almost completely worn down and still lying 

 undisturbed close to sea-level ; but the descrip- 

 tion given of it strongly suggests that it is a 

 somewhat unevenly uplifted peneplain, bearing 

 some linear residual mountains on its back, and 

 more or less dissected by its revived streams. 

 For example, " The High Eifel is a broad, flat- 

 arched dome, which descends southward as a 

 gently inclined plain towards the valley of the 

 Mosel ; beyond the Mosel, the same surface is 

 continued in the Hunsriick as a nearly horizontal 

 plain, rising wall-like in the high quartzite 

 ridges of the Hochwald " (p. 332). To exclude 

 a region thus described from the class of uplifted 

 and dissected peneplains makes one wonder 

 what conception the author attaches to this 

 category of forms. The report forms a very 

 serviceable guide for a physiographic excur- 

 sion over this district. It is in many ways 

 more satisfactory than the more elaborate essays 

 by Follman on the Eifel and by F. Meyer on 

 the Hunsriick {Forsch. dent. Landes und Volks- 

 kunde, VIII., 1894, 195-282; XL, 1899, 73-106), 

 which unfortunately leave much to be desired 

 in this respect. 



PHYSIOGRAPHY OF ACADIA. 



The general progress of physiographic de- 

 velopment that has been found applicable to 

 the Appalachian belt within the United States 

 by various observers is extended by Daly to the 

 provinces of New Brunswick and Nova Scotia 

 with the adjoining islands ('The Physiography 

 of Acadia,' Bull. Miis. Comp. ZooL, Harvard 

 Coll., XXXVIIL, 1901, 73-104, 10 pi., map). 

 The uplands of inner New Brunswick and the 

 ' southern plateau' of Nova Scotia are regarded 

 as areas of Cretaceous peneplanation, now up- 

 lifted and dissected ; while central New Bruns- 

 wick, together with certain areas now sub- 

 merged in bays, represent lowlands etched out 

 of weak rocks beneath the Cretaceous pene- 

 plain, and now partly drowned. The author 



