Rb & Sr concentrations were determined either by X-ray fluorescence or by isotope-dilution techniques. Concentrations or extreme Rb-Sr ratios were measured by isotpe dilution. Rb-Sr ratios have a precision of + or - 3%. 87Sr/86Sr were measured on a separate unspiked run; normalized to correspond to an 86Sr/88Sr of 0.1194 with a precision of + or - 0.0005