Septembee 25, 1896.] 



SCIENCE. 



449 



weaker internal strata. On tlie nortlieast 

 the enclosing ridge is nearly lost ; but on 

 the southwest it constitutes a well defined 

 semi- circular divide. Larminat describes 

 with much detail the various elements of 

 form thus developed. Outliers (temoins) 

 in front of the escarpment are. figured in 

 various stages of breaking down under the 

 cross-examination of the weather. Streams 

 that once drained outward, down the dip of 

 the dome, have been ' confiscated ' by the 

 headwater growth of the inner lowland 

 streams. A good figure is given of a dry 

 stream bed (oued=wady) on the outer 

 slope of the enclosing ridge, that maintains 

 a considerable breadth up to the present 

 divide, thus plainly witnessing a transfer 

 of great drainage area from consequent to 

 obsequent streams. 



The generality of these phenomena is not 

 referred to by the author. The unroofed 

 dome of the Weald, in southeast England, 

 repeats nearly all of them, even to the broad 

 beheaded valleys that notch the encircling 

 ridge; the few unlikenesses of two regions 

 depending more on the surface expres- 

 sion as determined by climate than on 

 differences in structure or in stage of de- 

 velopment. The region of the Swabian 

 Alps, dividing the drainage areas of the 

 Ehine and the Danube, exhibits escarp- 

 ments, benches, outliers and shifting di- 

 vides in remarkable perfection. One of the 

 greatest examples of the kind is described 

 by Dutton under the name of the ' San 

 E-afael Swell ' in his report on the High 

 Plateaus of Utah. Less notable examples 

 can be given in great number. 



GUAYRA CATAKACTS OF THE PARANA. 



Count P. Antonelli gives a spirited nar- 

 rative of his excursion in August, 1895, to 

 the Guayra cataracts of the Upper Parana 

 in southern Brazil (Mem. Soc. geogr. ital., 

 vi., 1896, 80-102). His route eastward 

 from Eosario on the Paraguay led for days 



through the virgin forests, passing occa- 

 sional settlements where yerha mate, or Para- 

 guay tea, was cultivated ; then by canoe 

 down the Yagatimi to the Parana, just 

 above the cataracts. Although visited by 

 a number of travelers, accounts of the place 

 vary greatly. Antonelli states that above 

 the falls the river is expanded to a breadth 

 of ten kilometers, flowing quietly among 

 many islands ; then it plunges suddenly 

 down twenty-two channels over broken 

 granite ledges, descending 25 or 30 meters 

 into a gorge not more than 60 meters wide, 

 through which all the waters are discharged 

 in foaming rapids to the lower river. A 

 route map by surveyor Mariotti and several 

 views from photographs by San Martin are 

 included. As is so often the case, personal 

 narrative is prominently brought forward, 

 technical geographical description is lightly 

 touched, and physiographical relations do 

 not seem to have been even dreamed of. 



AUSTRALIAN EXPLORATION. 



Exploration in western interior Australia 

 continues to reveal a great expanse of ' des- 

 ert ' having a varied topography, as sum- 

 marized by several recent writers (Trans. 

 Eoy. Geog. Soc. Austr., Victorian branch, 

 March, 1896). J. W. Jones outlines the 

 geographical results of the Elder exploring 

 expedition. J. A. Panton reviews ^Austra- 

 lia deserta.' A. J. Wright gives a narrative 

 of his journey to Coolgardie, in the new gold 

 field of western Australia. All tell of an 

 arid region, broken by bare mountains of 

 ancient rocks, attaining a height of three or 

 four thousand feet ; great intermediate areas 

 of limestone and sandstone, much denuded, 

 and holding salt lakes or dry lake beds in 

 the depressions. Even when the surface of 

 the basins is dry, salt water can usually be 

 found a few feet below, ' so that the enter- 

 prising miner, with his condenser, can now 

 depend upon the salt lake for a permanent 

 water supply.' At the base of the imper- 



