<p> An age of approximately 55K years was found for the St. Clair basin clays using helium isotope dating. This is about 5 times larger than the date obtained from the more accepted carbon-14 method and from other geological evidence. Diffusion of helium from crustal rocks against a flow of approximately 0.03-0.05 cm a· ' is the primary reason for this discrepancy. Mixing of the groundwater with a meteoric component has an opposite effect tending to lower the helium age. </p> / Thesis / Bachelor of Science (BSc)