It seems strange that natural history specimens as common and widely distributed as fossil bones have received practically no study by the mineralogist. Realizing that they are fossils, the mineralogist has evidently left them to the consideration of the paleontologist, but the paleontologist is concerned only with their form and has little if any interest in the material of which they are composed.
Very little is said in the literature as to the nature of fossil bones, but the belief on the part of many geologists is that they are silicified. This misapprehension is probably due to their superior hardness and specific gravity over that of recent bones.1 But as a matter of fact silicified bone is exceedingly rare. Of the fossil bones studied by the writer, which number roughly about 300, only three were found to be silicified. In stead of being silicified, fossil bones are phosphatized and . . .