46 STONE IMPLEMENTS [f.th. ans.15 



question of tho relation of tlic iuicient quarryiii}^' to the ])resent bed of 

 the rivulet; the second related to the significance of a series of depres- 

 sions observed along the u])i)er ])art of the 8loi)e a little above the 

 quarry level (as deteiiniiied at other i)oints) anil immediately below 

 the upper margin of the teri'ace slope. The place selected was about 

 200 feet farther up the gulch than the second trench, and where the 

 length of the slope was only SO feet and the heiglit about 40 feet. At 

 this point the Potomac l)Owlder bed outcrops at or but little above the 

 level of the stream bed, and it was thought that evidence of ancient 

 excavation might be found so near the present bottom of the gulch as 

 to indicate the comjiarative receutness of the work. Observations ou 

 this point are given in detail further on. 



As to the other question, it was surmised that the depressions along 

 the upper part of the slope marked the sites of ancient pits, and inves- 

 tigation showed that this surmise was not far wrong. The depressions 

 are in all cases a little higher up than the old pits and above the 

 bowlder bed level, and are apparently the result of miniature land- 

 slides, by means of which the original quarry pits were tilled up. 



The i)heuomena disclosed in this trench are quite interesting and 

 may be given in some detail. Entering the bank on the level of the 

 stream bed, we followed the surface of the gneiss for a nund)er of feet. 

 Within the first 10 feet patches of undisturbed Potomac bowlder 

 gravel remained on the gneiss surface. At about the twentieth foot the 

 bowlder bed began to thicken, and its upper surface rose with the slope 

 of the talus. The bank of the rivulet was between 4 and 5 feet in 

 height, and was compo.sed of loose heterogeneous refuse, which, as the 

 excavation advanced, was found to be rudely bedded with the slope as 

 indicated in the section (plate xv). The loose refuse was from 5 to 7 

 feet deep, and rested on the gneiss or the uneven surface of the bowl- 

 der bed. Broken cobbles, rude rejects, broken embryo implements, 

 and chips were ])retty evenly distributed throughout the mass. At 

 the twentyseventh foot the tioor of the (juarry made an abrupt descent 

 of 3 or 4 feet. 



In advancing beyond the twentyseventh foot the bottom of the 

 ancient quarry rose but slightly, and at the fortieth foot it was 10 feet 

 beneath the surface. The deeper parts were filled with loose material — 

 clay, gravel, and bowlders — intermingled with which were a number 

 of fragments including chips and broken, imfinished tools, but there 

 was not here or in the vicinity any very decided evidence of chipping 

 on the spot. The lowest point of this ancient pit was only 2 feet above 

 the present bed of the gulch at the nearest jioint. 



Between the thirtieth and the fortieth foot no features of particular 

 interest were encountered. As shown in the longitudinal section, a 

 number of pockets of shop refuse occurred between the twentyeighth 

 foot and the thirtyftfth. These may have been shop sites, but had 

 more the character of refuse descended from above into de^jressions or 



