Page:The Journal of geology (IA journalofgeology11893univers).pdf/30

the effusive rocks has created a disturbance in the melaphyre-basalt group that can only be quieted by the ejection of one of the members of the group, probably the melaphyres, from the position it now occupies. When this is done it is probable that the diabases will take the position thus left vacant, and the plagioclase-augite rocks will be found to occupy these places with respect to each other: the gabbros, the position of a deep seated rock, the diabases that of the corresponding holocrystalline effusive, and the basalt that of the hypocrystalline equivalent.