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Show 57 few inches to three or more feet, although diameters of 8 to 12 inches are the most common. Lengths of 10 to 20 feet are not unusual. Fossilized logs are not always mineralized, but it is common and characteristic for them to have high concentrations of carnotite along their central parts. They were sought for their uranium content when radium ore was Important. Vanadium commonly is concentrated in the outer part of the log and in places the surrounding standstone. Mineralized logs often constitute a good grade of vanadium ore, although the total tonnage produced from them is not large. The logs are found alone or in groups more or less isolated, as well as enclosed in larger ore bodies. They are of particular interest because they commonly show an alinement parallel to the trend of the ore bodies with which they are associated. Making due allowances for exceptions, orientation of the logs has been useful in extending bodies and in discovering new ones. In spite of the irregularity of the ore bodies with their relatively small size as compared to the intervening areas of barren sandstone, exploration has revealed a number of important deposits that were not exposed at the surface. The common practice in prospecting has been to search for vanad'ium mineralization exposed at the surface in the sandstone cliffs. It is natural that, because of the ease with which these outcrops can be found and explored, relatively little of the area of the outcrop remains untested. However, |