Before the arrival of the white men in America the use of silver was not general among the natives north of Mexico. Only rarely have silver objects been found in the prehistoric mounds. Discs and tablets of sheet silver have been found in Florida but they are believed to be recent. The Navajo Silversmiths learned their art centuries ago from Mexico an there has been Comparatively little change in either method or tools, the art being maintained in pure form by them. The geometric forms that prevail in their designs usually have significance; a triangle may represent a mountain or an arrow head;a cro9ss may indicate the morning star or the four quarters of the compass.