ABSTRACT

Sedimentary particles, in particular blocks and grains, are mostly formed by the disruption of consolidated rocks by physical forces. If these forces are not directed or influenced by one or more particular agencies, such as in anisotropic crystal structure or salty cleavage, they can be called random forces; and they tend to produce particles with random shapes. Simple probability theory indicates that, with 10 percent accuracy of measurement, 72 percent of the particles will be expected to be blade shaped, 1 percent to be equiaxed shaped and 27 percent to be tetragonal shaped. As the possible accuracy of measurement increases, the expected percentage of blade shapes increases and that of the other shapes decreases. With the requirements of the Zingg classification in its original fo m, the expected percentages are Class II 11.1 percent, Class III 22.2 percent and Classes I and IV together 66.7 percent.