TITLES AND ABSTRACTS OF PAPERS 167 



Mud-cracks and ripple-marks are much more abundant in the Beekmantown 

 and Stones River formations than has been heretofore supposed. The diffi- 

 culty of their recognition in certain field sections is probably due to the fact 

 that the beds are rarely exposed to view along the plane of the dip, except 

 when quarries have been opened up along the strike. Illustrations will be 

 given of "mud-cracked" areas in cross-section, and an attempt will be made 

 to show the possible evolution of ripple-marked and mud-cracked areas into 

 "edgewise conglomerates" and intraformational breccias. 



Presented in abstract extemporaneously. 



Discussion 



Prof. A. W. Grabau : Mr. Field's detailed and careful work on the structures 

 of the Paleozoic limestones is sure to be of much use in the determination of 

 the origin of these deposits. He is to be congratulated on his results. 



PLEISTOCENE AND POST-PLEISTOCENE GEOLOGY OF WATERVILLE, MAINE 



BY HOMER P. LITTLE^ 



(Abstract) 



This paper describes the fluvio-glacial, estuarine, and floodplain deposits of 

 Waterville and vicinity. 



The main mass of the fluvio-glacial deposits is found in an esker several 

 miles long. Many gravel pits occur along it, and in these are good cross-sec- 

 tions which have been studied in detail. 



The esker is bordered by marine clays and sands. These overlap the esker 

 and are separated from its gravels by an unconformity considered due to sub- 

 aerial erosion. Fossils from these clays have been identified and the localities 

 and altitudes at which they were collected carefully indicated. 



The altitude, as determined with the Y level, varied from 121 to 139 feet. 

 Over 25 species of invertebrates were recognized, and 4 genera of land plants. 

 The fauna indicates waters still cooled by melting ice, while the flora shows a 

 climate much like the present. 



A river terrace 115 feet above sealevel has been excavated in these older 

 clays and gravels by the Kennebec River. On this the larger part of Water- 

 ville is built. A narrow terrace about 35 feet lower is also recognized. 



Possible evidence of a readvance of the ice is reviewed, and the conclusion 

 drawn that such an advance can not be shown to have occurred in this area. 



The paper closes with an attempt to interpret in detail the history of the 

 region. 



Presented in abstract from notes. 



^ Introduced by E. W. Berry. 



Xrr— Bill. Gi-ol. Soc. Am., Vol. 28, 1916 



