Maech 13, 1908] 



SCIENCE 



407 



The Cirques and Bock-cut Terraces of Mt. 



Toiey, Mass.: B. K. Emerson, Amherst, 



Mass. 



The next paper was 

 The Lower Portion of the Paleozoic Sec- 

 tion in Northwestern New York: H. P. 



Gushing, Cleveland, Ohio. 



In Jefferson County, N. T., in the dis- 

 trict between Watertown and Alexandria 

 Bay, the Potsdam sandstone and the Low- 

 ville. Black River and Trenton limestones 

 are present in quite normal expression. 

 Between the Potsdam and the Lowville are 

 two additional formations. The lower of 

 these passes into the Potsdam by gradation 

 and is lithologically like similar "passage 

 beds" elsewhere in northern New York. 

 It consists of alternating sands and sandy 

 dolomites, varies in thickness from 15 to 

 75 feet, and has an erosion unconformity 

 at its summit. It is overlain by an impure 

 limestone formation which overlaps on the 

 district from west to east, reaches a thick- 

 ness of 125 feet, and holds a fauna not 

 hitherto noted in New York, which is ten- 

 tatively correlated by Dr. E. 0. Ulrich 

 with that of the upper Stones River forma- 

 tion of southern Pennsylvania. It has 

 close relationship to the Lowville forma- 

 tion above. The Chazy formation is ab- 

 sent, as is also the entire Beekmantown. 

 The physical break between the two forma- 

 tions is the most prominent one as yet 

 noted in the New York Lower Silurian. 

 The section was compared with those east 

 and south of the Adirondacks, and the 

 additional light which it throws on the 

 physical oscillations of the region was con- 

 sidered. Discussed by H. M. Ami. 



At 12:15 o'clock the society adjourned 

 for luncheon in the dining room of the 

 university, after which President Tight led 

 the way to the flat roof of one of the 

 pueblo-style dormitories, from which he 

 pointed out the geological features of the 

 surrounding country. 



At 2 o'clock the afternoon session began 

 with the reading of the annual address by 

 the retiring president, President Charles 

 R. Van Hise, of the University of Wis- 

 consin, who chose as his subject "The 

 Problem of the Pre-Cambrian." By re- 

 quest of the president, his address was 

 thrown open to discussion, and remarks 

 were made by A. C. Lane, A. C. Lawson, 

 A. P. Coleman, H. M. Ami and C. R. Van 

 Hise. 



The following papers were then read by 

 title : 



The Bed Sandstone Formation of South- 

 eastern Minnesota: C. "W. Hall, Minne- 

 apolis, Minn. 



The Geological History of the Bedstone 

 Quartzite: Frederick W. Sardeson, 

 Minneapolis, Minn. 



Geology of a Portion of Central Wyoming : 

 N. H. Darton, Washington, D. C. 



Some Features of the Geology of Arizona 

 and Western New Mexico along the 

 Santa Fe Bailroad: N. H. Darton, 

 Washington, D. C. 



After this the society ' listened to the 

 reading of a paper on 



Grenville-Hastings Unconformity : Willet 

 G. Miller and Cyril W. Knight, To- 

 ronto, Canada. 



The crystalline limestone and associated 

 pre-Cambrian sedimentary rocks of south- 

 eastern Ontario and the adjacent parts of 

 the province of Quebec, to which Logan, 

 and his colleagues long ago gave the names 

 of Grenville and Hastings series, have 

 never been satisfactorily classified as re- 

 gards their age. Recent work by the pres- 

 ent writers has shown that much at least 

 of what has been called the Hastings series, 

 consisting of limestones, conglomerates and 

 other fragmental rocks, is much younger 

 than, and forms a well-defined unconform- 

 able series with, the typical crystalline 



