Rb and Sr concentrations were measured by isotope dilution and X-ray fluorescence for samples of the McKinley sequence or the Mesozoic flysch, respectively. The isotopic composition of Sr in all flysch samples and most rocks from the McKinley sequence was measured on unspiked aliquants of powdered rocks. For granitic rocks with high Rb/Sr ratios the Sr isotopic composition was measured on a spiked aliquant of powder. Mass analysis of Sr whas done on an automated 23-cm-radius, stygmatic-focusing, 90 degree-sector, double-collector spectrometer utilizing a double-filament source.