42,000 > 45,000 7170 ± 300 W-1661. Jacksonville, Florida 5220 B.C
[RADIOCARBON, VOL. 9, 1967, P. 505-529] U. S. GEOLOGICAL SURVEY RADIOCARBON DATES IX PATRICIA C. IVES, BETSY LEVIN, CHARLES L. OMAN and MEYER RUBIN U. S. Geological Survey, Washington, D. C. This list contains the results of measurements made during 1965 and 1966. Samples are counted in the form of acetylene gas, as pre- viously, and ages computed on the basis of the Libby half-life, 5568 ± 30 yr. The error listed is always larger than the one-sigma statistical counting error commonly used, takes into account known uncertainty laboratory factors, but does not include external (held or atmospheric) variations. Unless otherwise stated, collectors of all samples are members of the U. S. Geological Survey. The authors are indebted to Mrs. Julia Hohl, who assisted in the preparation of this list and of the samples since the fall of 1966. SAMPLE DESCRIPTIONS A. Eastern U. S. W-1903. Sussex County, Delaware > 42,000 Wood from stump of cypress between Seaford and Middleford (38° 39' 36" N Lat, 75° 36' 12" W Long), Sussex County, Delaware. In clay overlain by sand and gravel. Coll. 1966 and subm. by Henry Hutchin- son,Sussex Soc. of Archeol, and History, Bethel, Delaware. Comment: wood probably grew during Sangamon Interglaciation. W-1542. Lafayette Square, Washington, D. C. > 45,000 Fresh-water peat from Lafayette Square (38° 53' 58" N Lat, 77° 02' 7" W Long), Washington, D.C. From upper part of peat above organic silt, alt ca. 50 ft. Peat contains pollen, mostly of spruce and pine, some of fir, and a few deciduous trees; also contains fresh-water sponge spicules and diatoms.
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