Febeuaey 26, 1897.] 



SCIENCE. 



361 



pointing out the disparity, at least until very 

 recently, in the relative amounts of investiga- 

 tion and interest bestowed upon ' man foods ' 

 and animal foods. He described the classes of 

 foods rated according to their fuel values, di- 

 gestibility, etc., and noted the divergence be- 

 tween price and actual food value of many 

 articles, some of them not luxuries. 



The papers announced on ' Volumetric Esti- 

 mation of Lead,' by J. H. Wainwright, and 

 ' Electrolytic Production of Alkali Nitrites, ' by 

 Wm. M. Grosvenor, were held over until next 

 meeting. 



Dtjeand Woodman, 



Secretary. 



GEOLOGICAL SOCIETY OF WASHINGTON, 58TH 

 MEETING, JANUARY 9, 1897. 



Me. Whitman Ceoss read a paper on ' The 

 igneous rocks of the Leucite Hills and Pilot 

 Butte, Wyo.,' in which he stated that the 

 rocks of the Leucite Hills occur as surface 

 flows and in volcanic necks or plugs. The 

 leucite rock described by Zirkel, 20 years ago, 

 is the least abundant type in the region, the 

 other varieties containing more or less pot- 

 ash feldspar, as pointed out by Kemp in his 

 recent communication to the Geological Society 

 of America. Chemical analyses of various rock 

 types were submitted, together with analyses of 

 the pyroxene and mica. 



The rock of Pilot Butte, an isolated point 

 near the Leucite Hills, was also described and 

 its chemical composition shown by an analysis. 

 This rock is closely related to the leucite rocks, 

 although containing much glass. 



In a large cavity of the leucite rock was 

 found a quantity of potash nitre, and on a pro- 

 tected face of the Boar's Tusk, a volcanic plug, 

 was observed a white coating of soda nitre. 

 The origin of these nitrates, whose mode of oc- 

 currence is so unusual, is not explained by any 

 observations made. 



This communication will soon be published 

 in some scientific serial. 



Mr. W. Lindgren read a paper on ' The Gran- 

 itic Rocks of the Sierra Nevada,' in which he 

 called attention to the large areas of intrusive 

 granitic rocks occurring along the Pacific coast 

 and to the fact that these intrusives are of com- 



paratively recent date, probably early Creta- 

 ceous. A map of the distribution of the 

 various kinds of granitic rocks in the northern 

 part of the Sierra Nevada was exhibited. It 

 was shown that, while some true granite exists, 

 the largest mass is made up of grano-diorite, a 

 rock intermediate between granite and diorite 

 or, more accurately, intermediate between a 

 quartz-mica-diorite and a quartz-monzonite, re- 

 cently defined by Brogger. 



W. P. MOESELL. 



U. S. Geological Survey. 



BOSTON SOCIETY OF NATUEAL HISTORY. 



A GENERAL meeting was held January 6th, 

 eighty persons present. 



Mr. A. W. Grabau read a paper on the sand- 

 plains of Truro, Wellfleet and Eastham. (For 

 an abstract see above p. 344.) 



Professor N. S. Shaler, in commenting upon 

 Mr. Grabau' s paper, said that his observations 

 agreed with those of Mr. Grabau as to the 

 origin of the sand plains. The slopes are due 

 to a complexity of causes and frequently can- 

 not be discriminated. The hypothesis of fresh- 

 water lakes and the ponding of streams was 

 rejected as inadequate. Professor Shaler said 

 that the agency of ants in the formation of 

 these sand plains was very great, and should 

 be considered in relation to any theory account- 

 ing for them. 



Mr. J. B. Wood worth spoke of the difiiculty 

 of making out the internal structure of sand 

 plains; he had observed that the gravels near 

 the head were coarser than those from other 

 parts. Mr. Woodworth compared the sand 

 plains of the Cape region as described by Mr. 

 Grabau with those he had studied in the Narra- 

 gansett Bay district. The hypothesis of fresh- 

 water lakes applies equally to the Narragansett 

 Bay district. The kettle holes indicate masses 

 of ice after the melting of the ice sheet. 



Prof. W. M. Davis claimed that the slopes 

 could be discriminated, but that they should not 

 be solely relied upon. 



Professor Shaler contended that the slope de- 

 pended upon the material, and that the original 

 angle is unreliable until the material is known. 

 The difference of height of sea level should be 



