Plate VI
PLATE VII
Plate VII. Photographs of three fragments of flags showing casts of ice crystals on the under side. All observations made on crystals of this kind indicate local differences in the forms of ice crystals presumably due to differences in the rate of freezing, in the texture of the mud and probably in variations in water content of the mud. Some crystals in the locality from which these specimens came, show pinnate secondary growths. Specimens shown here are from near the upper part of the Eagle Ford at a point about two miles north from the Chisos Mining Company's property. Brewster County, Texas. Slightly reduced.