Summary: The tholeiites of Dalmeny and Kinkell are considered to be a phase of the quartz-dolerite magma of central Scotland. They are re-described and shown to contain chlorophaeite. It is demonstrated by means of analyses and refractive index determinations that the residual glass is of acid composition in both cases—a conclusion which does not support some of the writings of Dr. Fenner on basaltic crystallization.