Grand Geyser

Some of them spout every year or so and some every few minutes.

The Grand Geyser, the greatest in the world, throws a volume of steam and boiling water three hundred feet into the air, and another, called Old Faithful, sends up an immense volume of steam and boiling water as high as a very high church steeple every hour.

Old Faithful keeps spouting for several minutes and the water falls back in clouds of steam and spray.

There are other geysers which throw up quantities of mud and that most of the geysers build up stony foundations about them formed of the minerals which are in their water.