278 W. J. McGee—Artificial Mounds of Northeastern Iowa. 
26, 31, 45, 49, 58, 63, 73, 154 and 325 yards respectively, one 
each; of 36, 38, 65, 85 and 100 yards, two each; of 14, 19, 32 
87 and 75 yards, three each ; of 28 and 60 yards, four each ; five 
dimensions of 44 yards each, and six of 35; of 12, 18, 30 and 
83 yards, seven each; of 25 and 50 yards, nine each; of 15 
and 23 yards, ten each; thirteen dimensions of 17 yards, four- 
teen of 20 yards, and sixteen of 40 yards each. Obviously such 
coincidences could not occur casually. Though the number 
of measurements here recorded is too small to base any far- 
either was simply, or had grown out of, the pace, or yard. e 
ssession of such a unit would not point to a race of very high 
intellectual culture, though to one widely removed from the 
lowest savages. 
The northern limit of the mounds of definite dimensions is not 
certainly known. The writer has sought vainly for evidence of 
the use of measurements in the most northerly of the mounds. 
His own examinations so far extend only to latitude 48° 30’ N., 
and there the mounds are of constant or related dimensions. 
The most northerly of the measured mounds are undoubtedly 
within Minnesota. 
we assume a slow southerly migration to have taken place 
in the Mound-builders, it will explain the evident increase 1n 
geometrical knowledge attested by the various works found in 
ing across the United States from north to south. Here we 
“ ts in po 
together with many other important considerations, lend sup- 
* Squier and Davis, “ Ancient Monuments of the Mississippi Valley,” pp. 9, 56. 
t Ibid., plates XVII and XXV; also the whole chapter descriptive of “ Sacred 
Enclosures.” t Ibid., p. 66. § Ibid., pp. 116, RET. 
