Basalt is a brownish rock of igneous origin.

Basalt is a brown rock of igneous origin.

The brunt of the controversy settled about the unstratified rocks-granitesand their allies-whichthe Plutonists claimed as of igneous origin.

Many still insist that lodes, particularly those containing gold, are of igneous origin, and point to the black and brown ferro-manganic outcrops in confirmation.

Far away in the west and north we could see high blue heights, probably of igneous origin from their forms, rising out of a plain.

By what train of investigations were geologists induced at length to reject these views, and to assent to the igneous origin of the trappean formations?