Jan. 2 and Feb. 6, 1874.] -*-'^ [Lesley. 



The Brown Hematite Ore Banks op Spruce Creek, Warrior's 

 Mark Run, and Half Moon Run, in Huntingdon and Centre 

 Counties, Pennsylvania, along the line of the Lewisburg, 

 Centre County and Tyrone Railroad. 



By J. P. Lesley, Professor Geology, University of Penna. 



{Bead before the American PJiilosopMcal Society, Jan. 2 and Feb.Q, 1874.) 



Preliminary Chapter. 



The district under examination, with an aiea of about one hundred 

 square miles, is bounded on the west by the Bald Eagle Mountain, on 

 the east by Tussey Mountain, and on the south by the Little Juniata 

 River, and the Pennsylvania Central Railroad. 



The Huntingdon-Centre County-line crosses it transversely from moun- 

 tain to mountain. The Hunthigdon-Blair County-line follows the river. 



Spruce Creek flows southward along the foot of Tussey Mountain. Its 

 branches. Warrior's Mark Run and Half Moon Run, cross the country 

 from Bald Eagle Mountain, along the foot of which their head waters 

 flow. Logan's Run flows at the foot of Bald Eagle Mountain into the 

 Little Juniata River near Tyrone. See large Map. 



The river and the two runs afford fine opportunities for three cross- 

 sections, represented in figs. 1, 2 and 3. These sections have been photo- 

 lithographed (like the map) to a very reduced scale for convenience of 

 publication, but were carefully constructed on the same vertical and 

 horizontal large scale, so that their geology may be relied on. 



The map was plotted with great care from the survey notes of Mr. 

 Franklin Piatt,* (as were also all the reduced local maps of the Ore 

 Banks, figs. 8 to 44) and adjusted with almost no variation to the rail- 

 road survey maps in the office of that experienced and most reliable Civil 

 Engineer, Mr. Leuffer, who located, constructed and has in charge the 

 completion of the L, C. C. and T. R. R., to whose courtesy I am in this 

 as in other cases, so largely and gladly indebted. 



The map is drawn in ten foot contour lines, determined by aneroid ob- 

 servations, based on the spirit levels of the railway lines, preliminary 

 and adopted. One set of aneroid observations was carried to the top of 

 Tussey from Pennsylvania Furnace; the rest of the mountain being drawn 

 in by rough trigonometi'ical observations from the Spruce Creek road. The 

 gaps in its terrace are all properly placed and their characteristic features 

 given : but slight variations in the almost dead level crest of the moun- 

 tain could only be indicated. The survey of the Spruce Creek Valley 

 was made rapidly and only for the purpose of assigning a proper value to 

 its topographical features, a new township survey by a corps of odometer 

 ■surveyors being the basis. Here a considerable adjustment had to be 

 made, which renders this part of the map of no authority, as against 



* Formerly an Assistant on the U. S. Coast Survey. 



