Sometime around 2.5 billion years ago, blobs of magma intruded into the older rock, forming plutons of granitic rock. Extensive exposures of this rock are found in the central part of the range. About 1.3 to 1.4 billion years ago in Late Precambrian, 5 to 200 foot (1.5 to 60 m) thick black diabase dikes intruded as well, forming the prominent vertical dikes seen today on the faces of Mount Moran and Middle Teton (the dike on Mount Moran is ). Some of the large dikes can be seen from the Jenny Lake and String Lake areas.