1926] Sequential Distribution of Formica exsectoides Foret 129 
while a line across its top measured 24 feet. This was one of a 
pair and the other measured 15 feet across the top and 47 feet 
about the base. Both these great structures were built up upon 
an old level charcoal hearth; and hence their age was limited. 
No such large accumulation of these vast works of mound- 
building ants seems to have been recorded elsewhere; but 
Wheeler figures a mound in New Jersey 1 m. x 3.25 meters and 
a mound of another species in Belgium as 2.15x9.8 meters. 
In Maryland the mounds made by this ant are not un- 
common in the wooded mountains of central and western coun- 
tries where the summer, visitor often evicts them with little 
regard for any claims that might be set up by these red and black 
original inhabitants so that in time not only the demands of 
agriculture but the thoughtless aspects of enjoyment of nature 
may combine to exterminate the present mound builders. 
In eastern Maryland one may find the mounds here and 
there in Baltimore County, near Baltimore, as along the hills 
West of the limestone valley in which lies Cockyesville, up the 
Beaver Dam Run, and north of Green Spring valley where a 
fine grass-grown mound was measured and photographed in 
1906 by Professor Philip H. Friese, along the North Run, a mile 
north of Stevenson. As described in a letter of that date this 
mound was about thirty inches in height and a perfect cone 
except for rounded top and evidently owed its steepness to being 
covered with grasses, some of which were not represented among 
the grasses of that neighborhood. And as above noted there are 
quite a number of small medium mounds near the shore below 
the Piedmont Plateau, in the region near Cowenton. While most 
of these mounds stand alone or a few in a group, an unusually 
populous settlement of ant’s mounds was found near Lutherville 
and Timonium, some nine miles north of Baltimore, by the late 
Professor Basil Sobers who called attention of the Baltimore 
Naturalists Field Club to this favorable place for study of these 
mound builders. 
However these ants were earlier known to the late Professor 
Philip Uhler, sometime Associate in Natural History in the 
Johns Hopkins University and Provost of the Peabody Institute, 
who told me that in his boyhood, when he lived at Lutherville, 
