1 882.] Geology and Palceontology. 755 



GEOLOGY AND PALAEONTOLOGY. 

 The Southern Limit of Ancient Glaciers in Pennsylvania. — 

 . At a late meeting of the Boston Society of Natural History, Pro- 

 fessor G. F. Wright, of Oberlin, O., gave an account of the dis- 

 coveries made last summer by him and Professor H. C. Lewis 

 concerning the southern limits of ice-action (otherwise called the 

 terminal moraine) in Pennsylvania during the glacial age. These 

 Investigations were made under the direction of Professor Lesley, 

 who has charge of the elaborate geological survey now in pro- 

 gress in that State. Previous to last summer Mr. Clarence King 

 had, first in 1876, through a paper of Mr. Wright's before this 

 society, called attention to the terminal moraine at Wood's Holl. 

 Subsequently Warren Upham, taking up this clue, had followed 

 it through Cape Cod and Long Isiand, where the line joined on 

 to that discovered by Professor Cook, of New Jersey, reaching 

 the sea at Perth Amboy just below New York, and crossing the 

 Delaware river at Belvidere, a little above Easton, Pa. From 

 this point the line of the terminal moraine was seen laid down 

 upon a map fifteen by ten feet, displayed for the first time to a 

 scientific society, crossing Northampton county by a general 

 north-western course to the center of Monroe county ; thence 

 westward, cross ng th L h gh fifta n m It * ibove Mauch Chunk, 

 and the Susquehanna twenty miles below Wilkesbarre ; thence 

 by a northwesterly course through Columbia county, rising to 

 the summit of the Alleghanies in Lycoming county and crossing 

 them diagonally through Tioga and Potter counties, where the 

 general elevation of the country is upward of 2000 feet. From 

 Potter county the moraine enters Cattaraugus county, N. Y., and 

 continues to trend northward as far as Little valley, six miles 

 north of Salamanca, where it makes a sharp turn to the south- 

 west, running nearly pai r to Colum- 

 biana county, Ohio. The whole length of the line explored this 

 last summer is about 40 > miles. The signs of glacial action ab- 

 ruptly cease along this line, and it is marked by a special accu- 

 mulation of unst ratified material composed of clay, scratched 

 stones and granite boulders which have been transported hundreds 

 of miles. North of that line the signs of glaciation are every- 

 where apparent ; south of it there are no scratched stones, no 

 transported boulders, and no "till" or boulder-clay. Where 

 streams cut through the line, however, boulders of granite and 

 quartzite have been transported bv water and deposited in terra- 

 ces ami deltas.' The gravel at Trenton, New Jersey, in which Dr. 

 C C Abbott has found palaeolithic implements, is in a delta ter- 

 race thus formed when the river was fifty feet higher than now. 

 Every stream to the westward u h ■ h rises in the glaciated region 

 and flows through the un; '. i< 1 it. 1 r< ;i<>n, has formed correspond- 

 lr »g terraces and deltas, an 1 is U of 'i it, -est. The lecturer urged 

 that thorough search for palaeolithic implements should be made 



