Upland elevations are covered with thin tills or ledge is exposed (Thompson, 

 unpublished) . 



Coarser glacio-f luvial surficial deposits occur along the northwestern 

 margin of the region (ice-contact sand and growth deposits) and in the 

 Androscoggin River Valley (outwash sands) . Ice-contact deposits may occur 

 buried beneath marine clay valley fills such as an esker that extends south- 

 west from the Androscoggin River into South Freeport (Gerber, 1979) . 



Soils: 



The soils of this region are dominated by loamy and clayey soils developed 

 on the marine clays. These soils include: Adams, Buxton, Scantic, Lyman, 

 Peru and Histosols. Poorly developed soils on bare ledge occur in ridge tops, 

 while sandy soils (Colton) and wet organic soils overly outwash and ice-contact 

 surficial deposits (U.S.D.A., 1967). 



Marine Geology: 



The marine geology of Region 1 is dominated by Casco Bay, a wave-dominated 

 neutral embayment. Several fine-grained estuaries lie along the landward margin 

 of the Bay (Cousins, Fore and Harraseeket Rivers) (Timson, in press). The 

 Royal and Presumpscot Rivers are delivering sediment to this basin at a high 

 enough rate so that their estuarine environments can be considered as deltas 

 although substantial portions of these deltaic (estuarine) environments are 

 sub-aqueous . 



Sedimentation rates within Casco Bay are variable, probably from to 

 2.8 cm/yr (Schnitker, 1974). S. D. Warren (1974) has measured suspended 

 sediment concentrations of the Presumpscot River. These concentrations vary 

 from .5 to 40 mg/1, the later figure occurring during spring freshets. 

 Timson (unpublished data) found that much of this sediment input from rivers 

 was deposited within the estuary or just outside of the estuary's mouth in 

 the inner Bay. Suspended sediment from the ocean floor of the estuary's 

 mouth in the inner Bay. Suspended sediment from the ocean floor also contri- 

 butes to sedimentation within the Bay. Ocean water suspensates contribute 

 from 2 to 6 mg/1, of sediment capable of being deposited within the Bay. 



Timson (1979) reports that unconsolidated shorelines along the inner Bay 

 margin are retreating annually at a rate of from .25 ft to 3 ft. The material 

 eroded from these shores also serves as a contribution to material being 

 deposited on the floor inter tidal and subtidal flats of Casco Bay. 



Hydrogeology: 



Four major rivers drain Region 1. The Androscoggin River passes through 

 the upper portion of the area. The Royal, Presumpscot and Fore Rivers drain 

 the remaining and major portions of the region. 



(Continued) 



2-D-2 



