GEOLOGICAL SOCIETY OF PENNSYLVANIA. 251 



GEOLOGICAL DESCRIPTION OF A PORTION OF THE ALLEG- 

 HANY MOUNTAIN, ILLUSTRATED BY DRAWINGS AND SPE- 

 CIMENS. By Edwakd Miller, C. E. 



As a recreation from duties of a more arduous charac- 

 ter, I have for some time past employed myself, during 

 hours of leisure, in collecting information concerning that 

 part of the Alleghany mountain which is crossed by the 

 Portage Railroad ; and this memoir, and the drawings 

 which accompany it, contain some of the results of my 

 observations. The deep excavations made for the Por- 

 tage, and the bold ravines and gorges with which the 

 mountain is serrated, aiford every opportunity which can 

 be desired for an examination, and I have endeavoured 

 to procure results which may be depended upon as accu- 

 rate, so far as they extend. The dip and bearings of 

 the various strata were ascertained by proper instru- 

 ments ; and the topographical details from correct manu- 

 script maps, and other data belonging to the state, and 

 now in the engineer's office at Johnstown. 



The sheet of drawings contains an outline map of a 

 part of the mountain (about 200 square miles) on a scale 

 of 1 mile to an inch. It comprises portions of Cambria, 

 Bedford and Huntingdon counties. The summit or crest 

 line of the mountain, which forms the eastern boundary 

 of Cambria county, is indicated by a vermilion trace for 

 a distance of 15 miles. The map also shows the courses 

 of all the streams ; the Portage Railroad, along which the 

 observations were taken ; the line of dip ; and the line 

 of bearing of the strata. 



The map is accompanied by an elevation or profile of 

 the crest line, drawn on the same horizontal scale as the 

 map, and a vertical scale of 400 feet to an inch. 



