W.F. McCollough Sand Gauge
Flexible, waterproof plastic card has sand grains ranging from very coarse sand to fine silt permanently fused on plastic card. Additional features include size classification for large clasts, bed thickness classification, roundness chart with actual sand grains, field checklist for organizing notes, geologic time scale, and two carbonate classification charts. Gauge measures 2.5” x 3.5” and has nylon string for carrying convenience.