Apbil 16, 1909] 



SCIENCE 



633 



Suaq^uehanna were not diverted from their south- 

 west courses. 



Along the Ontario lowland the Tertiary chan- 

 nels are almost entirely destroyed or obscured by 

 drift, but the valleys of Irondequoit, Sodus, Little 

 Sodus and Fairhaven are trenches across the 

 Niagara-Medina scarp which probably represent 

 the northward pre-Glacial flow. To-day only two 

 large streams pass across this rock ridge, the 

 Genesee and Oswego, both in new channels. It 

 seems probable that along the belt of Salina out- 

 crop the pre-Glacial tributary streams flowed east 

 or west as they do to-day. 



It was suggested that the " oversteepened " 

 walls of the bottom sections of the Finger Lakes 

 valleys were produced by the rapid down-cutting 

 of the streams during the Tertiary uplift. 



The third map showed the principal stream flow 

 as compelled by the ice sheets. A few strong 

 south-leading valleys were enlarged or newly cut 

 by the concentrated glacial waters, and the Alle- 

 gheny and Susquehanna systems were turned to 

 the south. In order from west to east the gla- 

 cially developed valleys are Cassedaga, Conewango, 

 Ischua, Canisteo, Cohocton, Cayuta, Cattatonk, 

 Tioughnioga. These southeastward drainage lines, 

 transverse to the primitive flow, were carved from 

 numerous, short, subsequent valleys by stream 

 flow forced to the southward by the ice-damming. 

 Such flow was effective during the advance of the 

 ice sheet, but stronger during the waning of the 

 ice; and probably more than one ice invasion has 

 been concerned. 



On the Ontario lowland the forced drainage was 

 west or east, alongside the ice margin. In the 

 Erie basin the later flow was all westward past 

 the ice front. In the Mohawk Valley the drainage 

 between Little Falls and Rome was turned from 

 west to east. 



The water-parting which in pre-Glacial time lay 

 in Pennsylvania has been so changed by glacial 

 flow that it now lies close to the Finger Lakes. 



These papers were discussed together by Pro- 

 fessors A. W. Grabau, J. W. Spencer, F. Carney, 

 A. P. Brigham, G. F. Wright, F. B. Taylor, A. P. 

 Coleman and H. L. Fairchild. 



At 12:40 o'clock the society adjourned for 

 luncheon, meeting again at 2:05 o'clock to con- 

 tinue the reading of papers. President Calvin 

 occupied the chair. The first two papers were 

 read by title. They were: 

 Some Physiographic Features of the Shawan- 



gunk Mountains : George Buebank Shatttjck, 



Poughkeepsie, N. Y. 



Nantucket Shorelines, III.: F. P. Gtjlliveb, Nor- 

 wich, Conn. 

 Then was presented: 

 Nantucket Shorelines, IV.: F. P. GtrLiiiyEB, Nor- 

 wich, Conn. 



The writer has not been able to continue as 

 fully as would have been desirable the detailed 

 study of the island of Nantucket and its changing 

 shoreline, on account of the cost of oft-repeated 

 observation and survey. Some results of further 

 study since the last report made to the society 

 were given. 



The strong north and northeast storms of the 

 past fall have closed the Haulover, and the tom- 

 bolo from Wauwinet to Coskata was completed 

 on November 12, 1908. Some old maps have been 

 studied with reference to the former eastward 

 extension of the oldland at Wauwinet, Coskata 

 and Folger islands. The changes on Great Point 

 since 1896 were compared with previous conditions 

 and with what may be expected in future. The 

 shoals between Nantucket and Cape Cod, and 

 between Nantucket and Martha's Vineyard and 

 the Hyannis shore are considered as attempts of 

 the sea to build tombolos. 



After this was presented: 

 Note on Striations, U-shaped Valleys and Hang- 

 ing Valleys produced by other than Glacial 

 Action: Edmund Otis Hovet, New York City. 

 The volcanic sand-blasts due to the eruption of 

 Mt. Pel6 produced striations and grooves in the 

 material over which they passed that strongly 

 resemble the striations and grooves produced by 

 ice action. The heavily burdened streams of the 

 Soufri6re of St. Vincent have carved out rock 

 channels of typical U-shape in the old lava flows 

 of the volcano. Hanging valleys have been pro- 

 duced by the sea eroding more rapidly than the 

 streams. 

 The paper was discussed by Professor A. Penck. 

 Then was read by title: 

 Historical Notes on Early State Surveys: Geobqe 

 P. Meerhl, Washington, D. C. 

 The next paper was: 

 The Iron Ores of Maryland: Joseph T. Singe- 

 WALD, Je., Baltimore, Md. (Introduced by W. 

 B. Clark.) 



This paper presented a brief summary of the 

 results of an investigation carried on during the 

 past season on the iron ores of Maryland under 

 the auspices of the Maryland Geological Survey. 

 Four classes of ore were recognized — limonite, 

 hematite, magnetite and siderite. The paper pre- 

 sented embraced a discussion of the character and 



