858 



SCIENCE. 



[N. S. Vol. XIV. No. 361. 



by superposition from a now vanished cover of 

 Cretaceous strata is rejected because fault 

 planes ' would, in the opinion of the writer, 

 afford the simpler explanation.' But while 

 simplicity is a strong recommendation in artifi- 

 cial mechanism, it cannot be logically employed 

 as a means of choice between two theories of 

 river development ; if that were so, no rival 

 could be found for the Gordian method of 

 locating the Susquehanna and other Appala- 

 chian rivers by antecedence. Fault breccias, 

 where they occur, may certainly exert much 

 influence on the development of river courses 

 in Connecticut ; but until their occurrence in 

 the central and eastern part of the State is 

 proved by something more trustworthy than 

 the graphic extension of systematic lines from 

 the western part, this explanation of stream 

 orientation may be regarded as standing in an 

 interrogative rather than in a demonstrative 

 attitude. 



LAKE WINNIPEG. 



Lake "Winnipeg, 260 miles long, with an area 

 of nearly 10,000 square miles or a little less 

 than that of Lake Erie, is a member of the 

 series of lakes that occupies an inner lowland 

 of the ancient coastal plain, marginal to the 

 great Laurentian highland of eastern Canada. 

 Reports by Dowling and Tyrrell give a num- 

 ber of physiographic details concerning the 

 Winnipeg basin ( * Report on the Geology of the 

 "West Shores and Islands of Lake Winnipeg,' 

 Geol, Surv. Canada, XI., 1901, F. * Report on 

 the east shore of Lake Winnipeg. . . .' Ibid, 

 G.). The lake is 710 feet above sea level, 

 with a genei-al depth of from 40 to 60 feet. 

 Its eastern border is relatively straight, al- 

 though minutely irregular in the smaller view. 

 The rock floor here is of Archean gneisses and 

 granites, with a few schists, all reduced to a 

 surface of small relief, over which post-glacial 

 lacustrine clays have been spread to an alti- 

 tude of 150 feet over the lake. The clay plain 

 is forested, but if cleared and drained it may 

 become ' rich agricultural land.' Further 

 eastward, the generally even but minutely 

 rugged Archean rises above the clays, first in 

 isolated knobs, then in larger patches, finally oc- 

 cupying all thesurface; it is severely glaciated, 

 bearing little drift, but with many small lakes 



in its hollows. The east shore of the lake is 

 frequently bordered by low clay cliffs ; but 

 rocks appear in low points and islands, be- 

 yond which there are many shoals. The west 

 shore of the lake is very irregular, a frayed 

 outline of Cambro-Silurian strata ; cross- 

 bedded standstones below, and even-bedded 

 limestones (Trenton) above. These rocks fre- 

 quently form bluffs, back from which the coun- 

 try is generally level, but rising slightly further 

 westward. Over this upland is a mantle of 

 boulder clay, showing faint lines of stratifica- 

 tion as if deposited in a body of water. The 

 boulder clay frequently assumes the form of 

 drumlins, and many of these are noted along the 

 lake shore and on islands, where they are cut 

 back into cliffs, while curved beaches are strung 

 along between them, as on the southeastern 

 coast of Lake Ontario. 



The outline of the western shore strongly 

 suggests an effective glacial erosion, by which 

 the Trenton border has been shaped, somewhat 

 as has been described by Chamberlin for similar 

 outcrops in southern Wisconsin. The similarity 

 of Winnipeg and its fellows to Onega and Ladoga 

 of northern Russia has often been remarked, 

 and seems to be increased as new details are 

 gathered. 



A PIEDMONT LAKE IN BAVARIA. 



WtJRM or Starnberger Lake, 15 miles south- 

 west of Munich, is one of several water-bodies 

 piedmont to the Alps on the upland of southern 

 Bavaria. It has recently been monographed 

 by W. Ule (' Der Wiirmsee (Starnbergersee) in 

 Oberbayern, eine limnologische Studie.' Wiss. 

 Veroffentl. Ver. f. Erdkuake, Leipzig, V., 1901, 

 211 p., 15 figs., 5 pi., atlas of 8 sheets). The 

 lake has an area of 57.1 sq. kil.; an altitude of 

 584 met., and a maximum depth of 123 met. It 

 lies in the Deckeaschotter, or oldest glacial 

 gravels, occupying part of a valley that was 

 primarily the result of stream erosion between 

 the first and second glacial epochs ; but the 

 valley has been much modified by deposits of 

 drift from branches of the Isar glacier during 

 the second and third glacial advances. Glacial 

 erosion is given small value in this distal portion 

 of the glaciated area. A slight deformation, 

 producing a depression along the mountain base, 



