| Pactola Dam is situated at a point along Rapid Creek where the valley narrows and the creek has cut through a resistant, northwest trending ridge. Rocks at the dam consist of a complex series of schists, slates and amphibolites lying in nearly vertical beds which strike in a northwest direction. There is a small fold in the right abutment that modifies the strike of the beds and causes the axis of the dam to cross some beds twice. The schistosity for the most part parallels the original bedding. The amphibolite schist rocks are hard, jointed and usually weathered to shallow depths. The slate beds contain abundant iron pyrite which weathers readily above the water table. |
