4 PROCEEDINGS OF THE PITTSBURG MEETING 



features over such a wide territory. A mong these members are the Green Crinoidal 

 limestone (Conemaugh) ah-eady mentioned, the Freeport coals and the Ferriferous 

 limestone (Alleghany), and the Pittsburg coal (Monongahela). 



The strictly economic phase of the trip consisted in visits to (1) a number of coal 

 seams and mines; (2) the McDonald oilfield, where an oil well was " shot;" (3) a 

 gas field and a pumping plant in connection with it; (4) the great coking ovens, 

 and especially the by-product coke ovens. 



Physiographic and Glacial Geology 



At Pittsburg, some 200 feet above the Monongahela and Alleghany rivers, are 

 marked rock benches or terraces, which are covered by deposits of clay, sand, 

 gravel, and boulders. These same terraces can be seen in manj' localities farther 

 up these two rivers and their main tributaries, the terraces rising upstream. The 

 same benches continue down the Ohio for some distance, and are seen following 

 northward along the Beaver, but they descend in their extension up that stream. 

 The explanation of these features given by I. C. White is that in pre-Glacial times 

 the river, formed by the junction of the Alleghany and the Monongahela, dis- 

 charged northward along the present Beaver valley into the Lake Erie basin. This 

 northward-flowing stream was dammed back by the ice-sheet and the attendant 

 terminal moraine which was deposited across this valley near Wampum. In the 

 waters thus held to a higher level by the glacial and morainic dams were deposited 

 the clays, sands, and gravels which now cap the rock terraces already mentioned. 

 The rock terraces themselves represent the lev^el to which the streams had eroded 

 their valleys at some time before the advance of the ice from the north ; but this 

 time was not necessarily that immediately preceding the ice-sheet, for there is 

 evidence of a period of increased erosion in which the stream had incised narrower 

 channels in the wider level represented by the terraces. R. R. Hice, who has 

 studied these terraces and the glacial phenomena along the Beaver, agrees with 

 White in the interpretation here outlined. 



In addition to the phenomena connected with the history of these rivers, the 

 general physiographic aspect of the plateau country west of the mountains was 

 studied and discussed, as were also the terminal moraine and its attendant features. 



Personnel of the Excursion 



The excursion was under the leadership of Dr I. C. AVhite, State Geologist of 

 West Virginia. Doctor White's intimate acquaintance with the details of the Coal 

 Measure stratigraphy, his unfailing courtesy, and his painstaking eff'orts to make 

 the excursion profitable and agreeable to each and every one who participated in 

 it, were subjects of constant remark. The excursionists are under obligations to 

 him for the success of the excursion, and to him and Mrs White for their hospi- 

 tality during the visit to Morgantovvn. Thanks are also due to J. R. INIacfarlane, 

 of Pittsburg; R. R. Hice, of Beaver, Pennsylvania; L. G. Haas, Superintendent 

 of the Baltimore and Ohio lailroad, Pittsburg; Mr Young and Mr Cummings, of 

 the Foust Oil Company, Pittsburg; F, G. Ross, engineer of the Apollo Natural 

 Gas Company, Templeton, Pennsylvania, and to (). W. Kennedy, General ^lan- 

 ager of the H. C. Frick Coke Company. 



The following persons participated in the excursion : 



