774 



SCIENCE 



[N. S. Vol. XXV. No. 646 



in the bottoms of all the valleys, whether 

 connected with glaciers or not. The pro- 

 cess gives rise to a series of terraces, uni- 

 form over wide areas. Such terraces have 

 often, and probably wrongly, been inter- 

 preted as evidence of earth movements. 

 In the self-contained basins of Central Asia 

 glacial epochs were characterized by en- 

 larged .lakes in which greenish clays were 

 deposited ; inter-glacial epochs by dimin- 

 ished lakes and by the deposition of red- 

 dish, subaerial strata upon the previous 

 lacustrine clays. A study of such alter- 

 nating lacustrine and subaerial deposits in 

 three widely separated regions leads to the 

 conclusion that the glacial period consisted 

 of an increasingly severe series of climatic 

 oscillations preceding the well-known de- 

 creasingly severe series. Coal and iron ore 

 occur interbedded with lake deposits. 

 This suggests that some of the coal beds of 

 more ancient times may indicate rapid 

 changes of climate such as those of the 

 Pleistocene and Permian glacial periods. 



Some Results from the Study of the Cam- 

 brian Brachiopoda: Chas. D. Walcott. 

 Read by title. 



Cryptozoon: Genera, Species, Relation- 

 ships: Henry M. Seelt. Read by 

 title. 



Crustacean Fauna of the Shawangunk 

 Grit in Eastern New York: John M. 

 Clarke. Read by title. 



Additional Footprints from the Carbonif- 

 erous Shales of Massachusetts: J. B. 

 WooDWORTH. Read by title. 



Occurrence of TJnuswUly Laxrge Calcite 

 Crystals in New York State: D. H. 

 NewtjAnd. Read by title. 



Origin of the Lead and Zinc Ores in Mis- 

 souri: E. R. Buckley. No abstract re- 

 ceived. 

 Professor Buckley's paper was discussed 



by Drs. H. C. Hovey and Ami. 



Asymmetric Differentiation in a Syewite 



Bathylith: H. P. Cushing. 



This syenite occurs in the mid-Adiron- 

 dack region, occupying some 100 square 

 miles of surface. The normal rock is a 

 highly feldspathic one, with about sixty- 

 three per cent, of silica. It is one of the 

 great pre-Cambrian intrusives of the re- 

 gion, of later date than the Granville sedi- 

 ments, and the Laurentian granite gneiss. 

 It shows contacts against anorthosite and 

 Grenville calcareous sediments on one side, 

 when it becomes basic, with a high content 

 of ferro-magnesian minerals; on another 

 side it cuts Laurentian granite gneisses and 

 becomes acidic, approaching a granite in 

 character and composition. In this granite 

 portion is a considerable anorthosite inclu- 

 sion, surrounded by basic syenite, which 

 grades into the normal acid variety. The 

 relations seem to point to incorporation 

 and assimilation of the adjacent rocks as 

 the cause of the asymmetry of the bathy- 

 lith. Intermediate rocks, such as anortho- 

 site soaked with syenite, are also found. 



Professor Cushing 's paper was discussed 

 by Dr. Lane. 



Formation of Leucite in Igneous Rocks: 

 Henry S. Washington. Read by title. 



Genetic Connections of Some Granitic 



Dikes: Alfred C. Lane. 



Near Huron Mountain, Marquette 

 County, the hornblende gneisses and schists 

 are cut by series of red granitic dikes. The 

 coarser pegmatitic ones cut the finer, and 

 may be regarded as products of the same 

 magma when the country rock had been 

 heated up and the magma cooled. 



Different Manifestations of the Ophitic 



Texture: Alfred C. Lane. 



The ophitic texture results when idio- 

 morphic feldspar is embedded in augite 

 crystals. These in their growth crowd be- 

 fore them corroded remnants of olivine, 



