May 7, 1909] 



SCIENCE 



751 



Evidence is adduced tending to show : ( 1 ) That 

 some chemical activities are accentuated by the 

 saturated condition of sediments beneath an ice- 

 sheet. Carbonation and hydration would be en- 

 hanced, and even oxidation may occur. (2) That 

 the great pressure to which unconsolidated ma- 

 terials of an earlier drift sheet are subjected by 

 a later invasion of ice is an important agent of 

 alteration. This pressure based on a conservative 

 estimate of the thickness of the ice amounts to 

 over nine thousand pounds per square inch. Not 

 only are these materials made compact, but they 

 are faulted and jointed. Furthermore, this density 

 increased capillarity which has operated in more 

 recent alterations. In addition to the pressure of 

 a superincumbent ice-mass, it is probable that 

 hydration has increased the pressure-effects. 



This paper was discussed by George D. Hubbard. 



A 'New Occurrence of Carnotite: Edgas T. 



Whebet. 



A supposed occurrence of autunite at Mauch 

 Chunk, Pa., has been investigated, and the ma- 

 terial found to be similar in character to the 

 Colorado carnotite. It occurs in layers of con- 

 glomerate at the top of the Mauch Chunk red 

 shale on the west side of the Lehigh River, one 

 mile north of the town, having been extracted 

 from intercalated lenses of black shale and gray- 

 wacke and deposited in fissures and porous beds 

 by circulating surface waters. The dark color of 

 these lenses is due, not to carbon, but to the pres- 

 ence of comparatively fresh hornblende, biotite, 

 etc., resulting from the disintegration of the meta- 

 morphic rocks of the highlands to the south and 

 east, during the arid climate prevailing in late 

 Mississippian times, and much of the vanadium 

 and uranium originally distributed through these 

 rocks is concentrated in them. As the western 

 deposits of carnotite occur in similar positions, 

 namely, in arenaceous formations overlying red 

 shales, it is suggested that they may have had a 

 similar origin. 



The Phenomena of Miolian Sand Drift : E. E. Fbee. 

 Wind-drifted sand moves by " saltation " or in 

 a series of leaps in a manner quite analogous to 

 that recently described by McGee for the sus- 

 pended matter of streams. The forms shown by 

 collections of such sand are of two main types: 

 (1) the large heaps or dunes, (2) the minor sur- 

 face figures, of which ripples form the best ex- 

 ample. Previous discussions of dune formation 

 are satisfactory except that far too little impor- 

 tance has been assigned to the eddy behind the 



dune. Many anomalous forms can be explained 

 as due to it. Ripple formation is probably con- 

 nected with the production in the moving air of 

 eddy systems analogous to the Helmholtz vortex- 

 surface. 



This paper was discussed by C. H. Richardson, 

 George D. Hubbard, J. H. Cook, G. K. Gilbert and 

 F. P. Gulliver. 



The following papers were read by title. 



The Mills Moraine, with Some General Remarks 



on the Olaciation of the Longs Peak Region of 



Colorado: Edwaed Oeton, Je. 



The Longs Peak group is a mountain mass with 

 several summits, lying in front or east of the 

 continental divide and connected with it by one 

 narrow and much-dissected ridge or spur. The 

 district is very wild and rough and existing maps 

 are of the most elementary sort and furnish no 

 accurate details. The highest peak is 14,271 feet 

 high and the mass as a whole, towering 1,000 or 

 1,500 feet above the general summit level of the 

 main range of the Rockies, is easily the domina- 

 ting point of northern Colorado. 



Separating the main range and the Longs Peak 

 group are deep gorges occupied by the head waters 

 of the Big Thompson and the St. Vrain rivers. 

 The heads of these gorges, winding around behind 

 Longs Peak, cut deeply into the connecting ridge, 

 and have nearly isolated the group from the main 

 range, of which it was once an integral part. 



The high valleys and cirques lying between the 

 main range and the western slopes of the Longs 

 Peak mass, offered an excellent gathering ground 

 for snows, owing to the great elevation of the 

 peak and the position of the gorges with reference 

 to the prevailing winds and storms. Great gla- 

 ciers developed there, and made their way out 

 north and south, curling around to the eastward 

 past the base of the great peak on either side, 

 and building magnificent moraines along their 

 flanks and termini. The nature, location and 

 general topographic features of these moraines is 

 discussed, and some evidences of periodicity in 

 their development is noted. 



"On the east side of the Longs Peak group, 

 located in a small cirque between the three highest 

 summits, a small but very active glacier has been 

 at work, and has built up a very beautiful moraine 

 system, entirely independent of the general gla- 

 ciation of the district. On account of this isola- 

 tion, these moraines offer a very good opportunity 

 for a study of the periodicity of the glacial phe- 

 nomena of the mountain areas of the west. 



