156 



SCIENCE. 



[N. S. Vol. XV. No. 369. 



by slow depression but also by the work already 

 then accomplished by subaerial erosion. Only 

 by supposing an extensive system of open 

 valleys to have been developed during the 

 earlier advance of wave work on the retreating 

 coast can satisfactory explanation be given 

 for the scattered arrangement of the remnant 

 islands on the abraded platform. 



THE SOUTHERN URALS. 



The excursion of the Kussian geological 

 congress turned attention to the Urals as an 

 example of an uplifted and dissected pene- 

 plain. Further information on this subject 

 is found in some 'Topographic notes on the 

 Ural Mountains,' by Purington (Bull. Amer. 

 Geogr. Soc, XXXIIL, 1901, 103-111). The 

 Bouthern extension of this old chain, where 

 the structure is as greatly disordered as else- 

 where, is for the most part a gently undulating 

 plain, the Orenburg steppe, hundreds of miles 

 in extent. Its surface is compared to that of 

 a calm sea, swept by huge, flat, crossing swells, 

 100 or 200 feet high and from two to four 

 miles from crest to crest. The general turf 

 cover of the nearly treeless plain is fre- 

 quently broken by low reefs of quartzitic 

 schists, traceable for long distances, and thus 

 revealing something of the underground struc- 

 ture. Some of the more decomposable schists 

 are weathered so deeply that mine shafts have 

 been dug 100 feet deep before blasting was 

 necessary. Water-worn gold-bearing gravels are 

 abundant on the undulating plain, but are 

 frequently too far from the streams for profit- 

 able washing. Low monadnocks of the more 

 resistant rocks occur in the region of the 

 steppe; further north in the forested Urals the 

 higher extension of the same peneplain is 

 dominated by dome-shaped monadnocks, rising 

 3,000 and 4,000 feet over the uplands. The 

 rivers of the steppe have now eroded broad 

 and shallow valleys from 50 to 200 feet deep; 

 the sides of the valleys are well defined where 

 they rise to the upland, whose borders are 

 dissected by ravines for a few hundred feet. 

 The valley floors are sheeted with gravels in 

 which the rivers meander freely. 



W. M. Davis. 



THE 8TRECKER COLLECTION OF LEPI- 

 DOPTERA AND THE AMERICAN MU- 

 SEUM OF NATURAL HISTORY. 

 Since the death of Dr. Herman Strecker, 

 many representatives of large museums have 

 visited his former home in Reading, Pennsyl- 

 vania, and commendable zeal has been dis- 

 played in their efforts to secure the Strecker 

 collection of lepidoptera for their respective 

 institutions. The heirs, however, have insisted 

 that no deviation would be made from the 

 original valuation placed upon the collection 

 by Dr. Strecker, namely $20,000. The Right 

 Reverend Dean Hoifman has authorized the 

 American Museum to purchase the collection. 

 This is not the first time that Dean Hoffman 

 has benefited the people of New York by gifts 

 of like character, and the silent appreciation 

 of the thousands that visit the superb exhibi- 

 tion of butterflies and moths which his gen- 

 erosity has made possible is itself a testimonial 

 of public gratitude. 



The growth of the Department of Ento- 

 mology within the last few years has been 

 phenomenal. In 1890 Mrs. M. S. Elliot do- 

 nated the 'Elliot Collection,' consisting of six 

 thousand local specimens, all reared from 

 caterpillars, and consequently as nearly abso- 

 lutely perfect as specimens can be — butter- 

 flies that are captured in the field are almost 

 invariably injured. In 1892 friends of the 

 Museum contributed some $15,000 toward the 

 purchase of the 'Harry Edwards Collection.' 

 This was a general collection of insects, but 

 contained some forty to fifty thousand butter- 

 flies and moths from various parts of the 

 world; among these were some three hundred 

 which were absolutely new to science. For 

 a long time this has remained the principal 

 part of the Museum collection. In 1891 a col- 

 lection of insects numbering some ten thou- 

 sand, and containing at least three thousand 

 North American Lepidoptera, was donated by 

 Mr. James Angus. Mr. Angus had made a 

 specialty of one genus of moths, the Catocala, ' 

 and in this one genus alone he had upwards of 

 fifteen hundred specimens. In 1897 Mr. Wil- 

 liam Schaus, then of New York, but now of 

 England, donated a remarkably complete col- 

 lection of Old World Lepidoptera, numbering- 



