870 



SCIENCE. 



[N. S. Vol. V. No. 127. 



as long as the printed editions lasted, this 

 proved an insuiBcient means of placing 

 them in the hands of the public. They are 

 now sold at five cents apiece for small 

 orders, or at two cents each in orders of a 

 hundred sheets or more, whether for the 

 same or for different sheets. Two dollars 

 for a hundred maps is certainly a merely 

 nominal price. Mne hundred sheets have 

 been printed. Lists of the maps may be 

 had on application to the Director of the 

 Survey. Orders for sheets must be accom- 

 panied by money order or cash for the exact 

 sum called for. 



Among the newer sheets may be men- 

 tioned Lexington and Stromsburg, Ne- 

 braska, including parts of Platte river 

 sprawling on in tangled channels its sandy 

 bed, with dissected uplands on either side 

 of its broad valley floor ; Pasadena, Cal., 

 showing what appears to be a great allu- 

 vial fan spreading out from the base of the 

 San Gabriel mountains ; Chester, Pa., 

 with a number of sub-parallel, transverse 

 streams draining the ' stripped belt ' of old- 

 land marginal to the New Jersey coastal 

 plain, as if they had been set on the old- 

 land rocks by superposition when the plain 

 stretched further inland. Many others are 

 of equal interest. The San Mateo, Cal., 

 sheet (part of the San Francisco peninsula) 

 is notable for the delicacy of its contour 

 lines, which appear to show much more de- 

 tail than usual and in this respect stand 

 in strong contrast with the free-hand con- 

 tours on the earlier Fort McKavett, Texas, 

 sheet. The same is true of the contrast be- 

 ween the irregular contours on the Pueblo, 

 Col., sheet, edition of 1896, and the over- 

 generalized contours of the same sheet, 

 edition of 1891. 



THE BARABOO DISTRICT, WISCONSIN. 



"The drift phenomena in the vicinity of 

 Devil's Lake and Baraboo, "Wisconsin," 

 {Chicago Journ. GeoL, V., 1897, 130-147) 



is a paper based on field work by students 

 of the University of Chicago, under the 

 direction of Professor Salisburj'. The 

 region is one of varied attractions, in- 

 cluding the Baraboo ridge, an ancient 

 quartzite monadnock on the peneplain 

 of pre-Cambrian North America, sub- 

 merged and buried in early paleozoic sedi- 

 ments, now exposed again by weathering and 

 denudation, and thus, like other ancient 

 fossil forms, organic or inorganic, presented 

 to us for study. The ridge is irregularly trav- 

 ersed by the terminal moraine of the 

 Green Bay glacial lobe, and the irregular 

 path of the limiting drift ridge is the sub- 

 ject of special study. Devil's Lake lies in 

 a deep gorge, excavated in preglacial time 

 (probably for the most part. Tertiary) 

 across the quartzite ridge ; the agent of 

 excavation being apparently the "Wisconsin 

 River, now displaced by heavy moraines in 

 the gorge. The quartzite ridge was some- 

 what sculptured in pre-Cambrian times, for 

 its slopes still hold a sandstone filling in 

 ancient ravines ; but we question whether 

 the gorge was so largely of ancient origin 

 as is implied (p. 141). The greater part 

 of its walls are free from sandstone ; and, 

 moreover, it would be altogether unlikely 

 that an ancient gorge, refilled during 

 burial, should have been again discovered 

 and occupied by a superposed river. 



BALCH, ON ICE CAVES. 



E. S. Balch, lately President of the 

 Geographical Society of Philadelphia, has 

 for some years made a special study of ice 

 caves, and now presents a summary of his 

 observations and researches (Ice caves and 

 the causes of subterranean ice, Journ. 

 Franklin Inst., Philadelphia, March, 1897) . 

 The popular belief that ice forms in these 

 caves only in summer is combatted. This 

 idea seems to be based on the fact that in 

 summer the air of a cave feels cool, while 

 in winter it feels warm ; but this is onlj' by 



