A 
re 
3 
ag 
a 
1878. ] Mound-Making Ants of the Alleghenies. 435 
in order to exhibit what seems very much like a deliberate and 
well planned system of engineering, in filling up the hole. The 
drawing is one-half natural size. At A, a, the original hill is 
shown, marking the southern limit of the foot-print. The work 
of filling up against this had begun. From the lower point A, 
marking the outline of an arc, were the following works: 4, a 
circular column one inch high, from the upper base of which, a 
broad bifurcated plateau was being extended; next to this was an 
oblong mound c, one-half inch high, and beyond that, marking 
the opposite limit of the track, a lunette d, one inch high. Beyond 
this, toward the base of the hill, and parallel with the arc å, c, d, 
was thrown an arc of like but smaller lunettes z, 7,2 At e and f, 
were lunettes similar to d, and at g, a scolloped mound. These 
elevations, with that at 4, &, surrounded the cavern 4, which was 
the deepest part of the cattle-track. The plan of operations is 
very plain; from the little raised columns and mounds figured 
above, the work of covering in could proceed with the greatest 
advantage. The elevations 4, c, d, were evidently guaged by the 
height of the edge of the hill at A, thus marking the depth of the 
track on that line. The diminishing depth was met by a corres- 
ponding lowering of the lunettes f, 2, 7, and at other points in the 
excavation the same facts held good. 
terre ee ey 
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Ma f ee Nor a a "melo 
cs ie cc i e 
: Fic. 6.—Engineering work ; filling up a break. 
The above operations began on Saturday morning; on Monday 
Morning the cavity was two thirds filled. Very strangely the 
work did not connect with the face of the break towards the sum- 
VOL. XII.-—No, VII, 31 
