Sediment core descriptions were based on examination of core samples under a binocular microscope in a laboratory setting. Grain size is based on the Wentworth classification. Sediment color is based on the Munsell Rock Color Chart and was made on wet sediments. The following descriptions are arranged by river system moving from river mouth upstream and in a northwest to southeast transect (see Figure 1 for general location).

Lostmans River First Bay Core (GLW705-FBLM1A) (Figure 5)

Figure 5. X-radiograph of the Lostmans River Core, First Bay (GLW705-FBLM1A), with a schematic diagram and brief sediment description on the left, and a preliminary summary of the environments indicated from an examination of molluscan fauna on the right. Note: Evaluation of molluscan fauna was made from unprocessed samples and therefore is biased towards larger specimens. Location of depth in x-radiograph is only approximate due to shrinkage that occurred after collection and prior to cutting. Legend shown below. [larger image]

Figure 5. (Continued) Legend for core schematics. [larger image]

Lostmans River Second Bay Core (GLW705-SBLM2A) (Figure 6)

Figure 6. X-radiograph of the Lostmans River core, Second Bay, with schematic diagram and brief sediment description on the left, and a preliminary summary of the environments indicated from an examination of molluscan fauna on the right. Note: Evaluation of molluscan fauna was made from unprocessed samples and therefore is biased towards larger specimens. Location of depth in x-radiograph is only approximate due to shrinkage that occurred after collection and prior to cutting. Legend shown on Figure 5. [larger image]

South Harney River Core near mouth (GLW705-SHR1A) (Figure 7)

Figure 7. X-radiograph of the South Harney River core near the mouth (GLW705-SHR1A), with schematic diagram and brief sediment description on the left, and a preliminary summary of the environments indicated from an examination of molluscan fauna on the right. Location of depth in x-radiograph is only approximate due to shrinkage that occurred after collection and prior to cutting. Legend shown on Figure 5. [larger image]

Depth (cm)	Description
0-14	Sandy mud, with high water content decreasing downward. Very fine white quartz sand to silt grains mixed with coarser dark organic clasts and calcareous material. Segment from 10-14 cm with increasing clay content. Scattered pieces of wood and whole shells. Fibrous plant material. (Dark yellowish brown - 10YR 4/2)
14-19	Very fine quartz sand to silt, very well sorted with almost no mud or clay present in upper-most part of zone, transitioning downward to a poorly sorted muddy clay with scattered silt, and calcareous and organic material. Rare plant material and shells. (Pale yellowish brown - 10YR 6/2 grading down to dark yellowish brown - 10YR 4/2)
19-60	Clayey mud to muddy clay with scattered very fine quartz sand to silt size grains. Sand/silt content decreases downward through segment. Large flakes of organic material, fibrous plant material and visible shells (abundant in some sections) and ostracodes. Minor laminations visible in lower portion of segment (50-60 cm) (Brownish gray - 5YR 4/1)
60-153	Organic clay with fibrous plant material. Scattered shells, but fewer than in overlying sediment. Laminae present through much of segment and scattered lenses of lighter colored very fine quartz sand to silt. Lower portion of segment (144-148 cm) appears burrowed; large lenses of very fine sand, shell debris and organic material in clay matrix. Scattered wood and areas of leaves and/or bark that parallel bedding plane. Occasional shell material. (Olive gray - 5Y 4/1 to olive black - 5Y 2/1)
153-165.5	Sandy, silty organic mud; blocky texture. Numerous scattered shells and some wood. (Olive black - 5Y 2/1)

Harney River Core near water monitoring station (GLW705-HR2A) (Figure 8)

Figure 8. X-radiograph of the Harney River core, near the water monitoring station (GLW705-HR2A), with schematic diagram and brief sediment description on the left, and a preliminary summary of the environments indicated from an examination of molluscan fauna on the right. Note: Evaluation of molluscan fauna was made from unprocessed samples and therefore is biased towards larger specimens. Location of depth in x-radiograph is only approximate due to shrinkage that occurred after collection and prior to cutting. Legend shown on Figure 5. [larger image]

Depth (cm)	Description
0-86	Organic mud to clay, with silt to very fine quartz sand. Disseminated organic flakes, scattered shells, ostracodes, foraminifers and plant material present. Very high water content decreasing slightly downward; fibrous plant material and cohesiveness of sediment increases downward. Some zones with thin laminations of very fine sand and/or silt. (Olive black - 5Y 2/1)
86-98.7	Gradational with overlying segment. Cohesive organic mud to clay, with silt to very fine quartz sand grading downward to a crumbly, coarser-grained clayey very fine sand to silt. Shell and wood content relatively high through this section, with abundant foraminifers, ostracodes, and freshwater gastropods. Some zones with thin laminations of very fine sand and/or silt. (Olive black - 5Y 2/1 to brownish black - 5YR 2/1)

Shark River Core near entrance to Ponce de Leon Bay (GLW705-SR1A) (Figure 9)

Figure 9. X-radiograph of the Shark River core near the entrance to Ponce de Leon Bay (GLW705-SR1A), with schematic diagram and brief sediment description on the left, and a preliminary summary of the environments indicated from an examination of molluscan fauna on the right. Location of depth in x-radiograph is only approximate due to shrinkage that occurred after collection and prior to cutting. Legend shown on Figure 5. [larger image]

Depth (cm)	Description
0-66	Organic mud, with relatively high water content, decreasing downward. Scattered very fine quartz sand to silt-sized grains scattered throughout, most sub-rounded to well-rounded, increasing downward through section. Becomes clayey mud in some segments. Fibrous plant particles and small fragments of bark and/or wood disseminated in mud. Some shell material, foraminifers and larger pieces of wood. (Olive gray - 5Y 4/1 to olive black - 5Y 2/1)
66-70	Muddy clay, with laminations of slightly lighter and darker material. Rare fibrous plant material present and scattered shells. (Olive gray - 5Y 4/1 and 5Y 3/2)
70-103	Organic mud, with relatively high clay content and very fine quartz sand to silt size grains. Proportions of clayey mud to silt fluctuate throughout segment. Fibrous plant material, shells, and wood present. (Olive gray - 5Y 4/1)
103-113.5	Muddy very fine quartz sand to sandy organic mud; sand grains are subrounded to rounded. Scattered fibrous plant material and organic clasts throughout, and scattered large clasts of peat in sand matrix. No visible shell material. (Light olive gray - 5Y 6/1 to olive gray - 5Y 4/1)

Shark River Core north of main channel (GLW705-SR2A) (Figure 10)

Figure 10. X-radiograph of the Shark River Core, north of the main channel, (GLW705-SR2A), with schematic diagram and brief sediment description on the left, and a preliminary summary of the environments indicated from an examination of molluscan fauna on the right. Location of depth in x-radiograph is only approximate due to shrinkage that occurred after collection and prior to cutting. Legend shown on Figure 5. [larger image]

Depth (cm)	Description
0-96	Sandy organic mud, with relatively high water content, decreasing downward, becomes relatively cohesive at 28 cm. Very fine quartz sand to silt-sized grains intermixed in mud matrix. Fibrous plant material and scattered wood, shells, ostracodes and foraminifers, abundant in some segments. (Brownish black - 5YR 2/1)
96-106	Peaty organic mud, gradational with overlying segment. Texture is spongy, with no visible sand or silt grains. Shells and plant material are abundant. Freshwater gastropods visible in section from 102-106 cm. (Olive black - 5Y 2/1)
106-114	Transitional, peaty organic mud from above mottled with muddy clay from below. Freshwater gastropods abundant throughout. Content of peaty mud decreases downward as muddy clay increases, transitioning to underlying section. (Olive black and brownish gray - 5Y 2/1 and 5YR 4/1)
114-132	Muddy clay, with scattered silt grains. Clay content increases downward as mud content decreases. Abundant freshwater gastropods, decreasing slightly in abundance downward. Bundles of fibrous plant material and root casts are perpendicular to bedding plane and appear to be in situ. (Brownish gray - 5YR 4/1)
132-144	Clay, firm with fibrous plant material oriented perpendicular to bedding plane and probably in situ. Scattered shell material. (Olive gray - 5Y 4/1)