pip ^o.' 22]' CORALVILLE RESERVOIR — CALDWELL 87 



Drift Plains (Eaisz, 1951, map), cutting deeply into the limestone 

 below, thus producing a pattern of high, rocky cliffs and steep bluffs. 

 An extensive network of minor tributaries has created a series of 

 confluent canyons and high, supervening ridges, the latter providing 

 as much as 200 feet of relief. Above the conservation pool, the valley 

 is characterized by large areas of low bottom lands bounded by 

 eroded hills. 



Before European cultivation much of the area was heavily forested. 

 Even today, only the ridge tops and the more accessible bottom lands 

 have been denuded. The river bluffs and lateral canyons support 

 a heavy growth of oak, hickory, and maple with much underbrush 

 and second growth resulting from sporadic logging activities. 



ARCHEOLOGICAL SITES 



Archeological interest in the problem area is of long standing. In 

 the last quarter of the 19th century the aboriginal mound structures 

 of Johnson County were the subject of great local interest and nu- 

 merous but casual excavations (Davis, 1883; Thomas, 1887; Starr, 

 1892). Shortly after the turn of the century, intensive reconnais- 

 sance, confined to an area substantially coextensive with the projected 

 conservation pool, resulted in a more satisfactory systematization of 

 data (Ward, 1904). Currently, a reevaluation of the earlier work, 

 by Dr. Robert Tidnick of the University of Iowa School of Medicine, 

 has added materially to the factual inventory. Dr. Tidnick's un- 

 published data have been incorporated freely into the following 

 presentation. 



The preliminary examination of the reservoir by the River Basin 

 Surveys located 9 archeological sites; 10 additional sites were re- 

 corded by interested amateurs (Wlieeler, 1949, p. 4). The current 

 intensive reconnaissance brought to light 10 supplementary occupa- 

 tion areas (fig. 10). It seems probable that still other aboriginal 

 sites must exist in the lesser-known upper pool and on the ramifying 

 highlands peripheral to the reservoir. 



In addition to reconnaissance activities, the 1956 field party made 

 extensive tests of three of the previously reported manifestations 

 (13JH2, 3, and 4) and a complete excavation of one of the newly 

 discovered sites (13JH202). Limited testing was also done at sites 

 13JH201, 203, 204, 205, 206, and 207. A distinct effort was made to 

 relocate sites reported by Keyes (ibid., fig. 1), but lacking detailed 

 legal description, success was minimal. 



THE HENRY AICHER SITE (13JH1) 



These mounds, known locally as the Aicher group, are situated just 

 below the dam site (ibid., p. 5) and hence were not excavated. The 

 earthen structures occur at the crest of a high, narrow ridge separat- 



