H. B. B ashore — Harrisburg Terraces. 99 



The second terrace, 46 feet above the river, is not very 

 plainly marked : one of the city streets however was originally 

 graded from its level. The bed is composed of gravel, some 

 granite and gneiss,* and contains large and small bowlders all 

 rounded, and is capped by two or three feet of fine loam. 



The third terrace, 90 feet above the river forms the plane 

 for two of the city streets (Fifth and Sixth). This deposit, 

 which gives a good perpendicular exposure of 15 feet, is com- 

 posed of fine gravel and contains some granite and gneiss ; a 

 few rounded bowlders, two to three feet in diameter appear in 

 it and the whole deposit is capped by four or five feet of fine 

 clay : almost all the bowlders occur in the gravel. 



The three terraces just described are placed in the interval 

 between the river and the hill, but the highest or fourth terrace 

 is situated on the brow of the hill itself. 



The fourth terrace, 130 feet above the river — 420 A. T. — is 

 well exposed by the cutting of several streets and shows the 

 gravels resting upon the slate. The deposit is about 20 feet 

 thick and is capped by fine brick clay. The gravel bed, espe- 

 cially at its upper part, presents a peculiar white appearance 

 compared to the overlying clay — the line of junction between 

 the gravel and clay being very distinctly marked. The gravel 

 contains considerable quartz, some granite and gneiss pebbles, 

 but none were found more than two or three inches in diam- 

 eter ; some rounded bowlders, two to three feet in diameter 

 occur in the deposit, mostly in the gravel, although several 

 were found in the clay. Above this joint, 420 A. T., on the 

 eastern side of the river there was not found any further evi- 

 dence of water action although careful search was made over 

 the adjoining hills : on the western side, however, as I stated 

 in a former report to the State Geologist of Pennsylvania, I 

 found, on a slate hill at 14S feet above the river, a number of 

 small rounded pebbles, one of which was of gneiss ;■ it is possi- 

 ble, however, that their transportation was due to human 

 agency. I may add that the mountains both north and south 

 of the city were carefully searched for " shore-lines " but the 

 result was negative in every instance. 

 West Fairview, Pa., Nov. 1, 1893. 



* Granite and gneiss do not occur in the Susquehanna Valley above this point 

 except as transported rock from regions farther north. 



