October 9, 1896.] 



SCIENCE. 



525 



OEIGIN OF LAKE ZURICH. 



The discussion of this problem by Aeppli 

 has been noticed in Science. Preller now 

 dissents from some of the conclusions of 

 the Swiss geologists, and maintains that 

 he has identified deposits of ' Deckenschot- 

 ter ' (first glacial epoch) in the trough of 

 the lake valley, and hence that the valley 

 must have attained its present general form 

 by fluviatile erosion before the earliest gla- 

 cial invasion (Q,. J. Geol. Soc. London, lii., 

 1896, 556-586). He attributes the lake 

 basin to a deformation of the valley, here 

 following Heim and Aeppli. In curious con- 

 trast to Geikie and Wallace, who place no 

 value upon such deformation or upon un- 

 equal subsidence, Preller allows glacial ero- 

 sion no share in excavating the lake basin, 

 and does not even present arguments for 

 the exclusion of this important agency. The 

 main points of this essay, the occurrence of 

 ' Deckenschotter ' in the deep valley trough, 

 and consequently the great abbreviation of 

 the first interglacial epoch, will doubtless be 

 •discussed by Swiss observers on the ground. 



DUST AND SAND STORMS. 



Dust and sand storms in the western part 

 of the United States are described by J. A. 

 TJdden, with special reference to the geo- 

 logical significance of these phenomena 

 (Pop. Sci. Monthly, Sept., 1896). He es- 

 timates that the dust in a cubic mile of 

 lower air during a dry storm weighs at least 

 225 tons ; while in severe sand storms the 

 :Solid contents in the same volume may 

 reach 126,000 tons. At Yuma, Ariz., any 

 high wind, without rain, generally blows 

 clouds of dust. At Ontario, Cal., there are 

 from twelve to forty dust storms in a year. 

 The brief dust squalls in the Eastern States, 

 preceding a thunder storm, are in the arid re- 

 gion replaced by dust storms lasting twenty 

 or thirty hours. One observer gives local 

 color to his phrase : ''A strong wind was 

 anade thick and yellow by flying real estate." 



The physiographic value of the wind in 

 drifting sand is illustrated in an account of 

 the Takla-makan desert. Central Asia, by 

 Sven Hedin (London Oeogr. Journ., viii, 

 1896, 264-278). He finds that shallow 

 lakes occur at the western base of the 

 desert mountains, while the eastern base 

 and slopes of the ranges are encumbered 

 with sand hills, carried by the prevailing 

 northeast or east winds. The widespread 

 sand hills of our western plains were abun- 

 dantly described by early explorers; for ex- 

 ample, Warren, in 1855, '56 and '57, but 

 they are less heard of to-day, when the 

 railroads carry travelers quickly across the 

 plains to the more varied scenery and prob- 

 lems of the mountains. 



PHYSICAL GEOGRAPHY OF NEW YORK STATE. 



The American Geographical Society turns 

 attention to home study in an essay by R. 

 S. Tarr under the above title (Bull. A. G. S., 

 xxviii., 1896, 99-129), the first of a prom- 

 ised and welcome series. The State is di- 

 vided into eight provinces, named Long 

 Island, Gneissic Highland, Taconic, Cats- 

 kill, New York-Pennsylvania Plateau, Lake 

 Shore Plains, Mohawk Valley and Adiron- 

 dack ; each of these is briefly characterized. 

 The drainage system is then described. 

 The geological development of the state is 

 concisely explained in eight pages, and the 

 essay closes with four pages on climate. 



GEOGRAPHY FROM NATURE. 



In the same Bulletin, R. E. Dodge urges 

 the importance of studying ' Geography 

 from Nature ' (p. 146-156), and mentions 

 a number of localities near New York city 

 where such study can be undertaken to ad- 

 vantage. Tarr advocates the same method, 

 emphasizing the value of a training in field 

 geology, in an article on the ' Teacher's Out- 

 fit in Physical Geography ' (School Review, 

 iv., 1896, 161-172, 193-201). With simi- 

 lar intention, the undersigned has prepared 



