1926J Sequential Distribution of Formica exsectoides Forel 131 
the two settlements were not of remotely different origin, but 
probably all of one general society. 
In the larger town 157 mounds were enumerated of which 
95 were occupied and 62 deserted while in the village only 27 
mounds were found; of these 22 were occupied, and 5 deserted. 
The larger mounds were in the larger settlement, while the 
village had the appearance of being a more recent growth from 
immigration. 
In size the mounds varied from 1 to 8 feet in diameter and 
4 to 24 inches in vertical height. 
Three general types of architectural effect were noted. 
Some mounds were free from vegetation and showed fine conical 
forms the resultant of the untiring efforts of the ants to carry up 
onto the mound mouthfulls of earth and bits of stick and dead 
leaf as well as large bits of stone and other objects to be found 
on the surface of the ground near the mound, counteracted more 
or less by the down rolling and washing of the materials in the 
usual process of denudation of hills of all sizes. When the sub- 
soil is red the mounds are red, when white, white, and again the 
collections of small sticks may give grey effects. 
A second type of mound common in grassy glades presents 
more abrupt sides and artificial, tower-like contours from the 
combination of the above factors complicated by the upgrowth 
of certain grasses and other plants, as peppergrass, which tend 
to holding the down-rolling materials in steep slopes. A third 
and rare aspect is that of the mound partly coated over with 
moss which makes the natural surface more resistant to denu- 
dation and tends to emphasize differences in slope between the 
faces of the mounds that do and do not support moss. 
While the typical mound is nearly circular many are much 
elongated as if made up of the fusion of two formerly separate 
cones: while others elongate down steep slopes of the ground. 
Changes in Distribution of Ant Mounds in the Timonium 
Ant Community in 15 Years. 
The census of the mounds of the entire region made in 1905 
showed 184 mounds of which 117 were occupied and 67 deserted. 
A second census made by several students in 1920 recorded 
