ABSTRACT The Meadowcroft Rockshelter in southwestern Pennsylvania is best known for its pre-Clovis occupation. Potentially important later times the recovery of maize macrobotanical remains from higher strata dating as early 4th century BC based on radiometric radiocarbon ( 14 C) dates wood charcoal. These have been considered to be potentially old earliest microbotanical evidence Michigan, New...

Closely spaced samples on millimeter scale across the Cretaceous-Tertiary boundary clay in Denmark were analyzed by instrumental neutron activation analysis. The results show a strong correlation between Cr and Ir while Co, Zn, As, Sb Au are correlated with Fe. elemental peaks for Ir-Cr Fe separated 6 mm. peak is found burrow-fillings at lowermost part of clay. Chromite grains extracted from bo...