• Sample numbers 1&2 were prepared with kaolin as a base to ensure uniform samples. Assurance of uniformity was necessary to explore the feasibility of conducting a soils reference sample program.
  • Sample numbers 3 through 64 were prepared with Maryland clay as a base. The soil was obtained in the vicinity of Gaithersburg, Maryland. Variations between samples were obtained by the addition of fine sand, or organic material as seemed appropriate.
  • Sample numbers 65&66 were prepared from clay obtained from southeastern Ohio. Sample 65 obtained 100% of the Ohio soil, while sample 66 included 70% Ohio soil and 30% Maryland red clay.
  • Sample numbers 67&68 were prepared from topsoil obtained from western Illinois.
  • Sample numbers 69&70 were prepared from soil obtained from Albany, New York.
  • Sample numbers 71&72 were prepared from soil obtained from New Jersey.
  • Sample numbers 73, 74, 79, 80, 81 & 82 were prepared from soil obtained locally.
  • Sample numbers 75&76 were prepared by blending 75% local soil with 25% New Jersey soil.
  • Sample numbers 77&78 were prepared from soil obtained from Maine.
  • Sample numbers 83, 84, 85, 86, 87, 88, 89, 90, 95 & 96 were prepared from topsoil obtained from Glenn Dale, Maryland.
  • Sample numbers 91&92 were prepared from topsoil obtained from Gaithersburg, Maryland.
  • Sample numbers 93&94 were prepared from topsoil obtained from Sand Hill, Maryland.
  • Sample numbers 97&98 were prepared from blending 86% Maryland topsoil, 13% kaolin and 1% bentonite Maryland clay.
  • Sample numbers 99&100 were prepared from topsoil obtained from Silver Spring, Maryland.
  • Sample numbers 101&102 were prepared from topsoil obtained from Silver Spring, Maryland.
  • Sample numbers 103&104 were prepared by blending 61% clay material obtained from Culpeper, Virginia with 39% Maryland topsoil.
  • Sample numbers 105&106 were prepared by blending 94% shredded topsoil obtained from Glenn Dale, Maryland with 6% topsoil obtained from Sand Hill Maryland.
  • Sample numbers 107&108 were a clay material (composed of illite and kaolinite, with quartz) obtained from Sand Hill, Maryland.
  • Sample numbers 109 through 112 were a clay material obtained from Annapolis,Maryland.
  • Sample numbers 113 through 116 consisted primarily of a clay material obtained from Annapolis,Maryland.
  • Sample numbers 117&118 were a ground fire clay material obtained from Annapolis, Maryland.
  • Sample numbers 119&120 were a Boston blue clay material obtained from Boston, Massachusetts.
  • Sample numbers 121&122 were prepared by blending 44% fill dirt obtained from Hyattsville Maryland, 31% clay material obtained from Annapolis, Maryland, 16% Boston blue clay and 9% buckshot clay obtained from Vicksburg, Mississippi.
  • Sample numbers 123&124 were a clay material obtained from Gaithersburg, Maryland.
  • Sample numbers 125 - 130 were a clay material obtained from Annapolis,Maryland.
  • Sample numbers 131 & 132 were prepared by blending a bonding clay material obtained from Cedar Heights, Ohio with mica material obtained from Annapolis, Maryland.
  • Sample numbers 133 & 134 were a black clay material obtained from Crofton, Maryland.
  • Sample numbers 135 & 136 were prepared by blending ground fire clay material obtained from Oak Hill, Ohio with screened sand obtained from Hanover, Maryland.