Pegmatites are a common occurrence within granodiorite of the Late Jurassic and Early Cretaceous Eagle Plutonic Complex. They occur as irregular intrusions from a few centimetres to several metres wide and are best exposed along railway cuts between Romeo and Coquihalla and along either side of the Coquihalla River.

The pegmatites comprise pink orthoclase, milky white, massive quartz and muscovite in crystals up to five centimetres wide. Locally, they exhibit a gradation into the granodiorite and probably intruded at a late stage of consolidation of the pluton.