Yet strange to say, of all the meteorites that have been seen to fall only nine belong to the group of Siderites or Iron Meteorites, though the three largest meteorites known, Peary's meteorite from Cape York, Greenland, weighing 37-1/2 tons, the meteorite lying on the plain near Bacubirito, Mexico, weighing about 20 tons, and the Willamette, Oregon, meteorite, weighing 15-1/2 tons all belong to this group. Moreover, all the Canyon Diablo meteorites, which are strewn concentrically around Coon Mountain crater in northern Arizona to a distance of about five miles, are members of this same group. Coon Mountain or Meteor crater itself is a perfectly round hole, about six hundred feet deep and over four thousand feet in diameter and was formed, it is believed, by the impact of a huge meteorite which has never been found. It is believed that the Canyon Diablo meteorites, of which there are nearly four hundred individuals in the U. S. National Museum alone, were all members of this same fall. It is possible that these meteorites of the Canyon Diablo district, with the huge meteorite that produced the crater itself, formed the nucleus of a comet that struck the earth not more than five thousand years ago, according to the geological evidence.