1) Argillaceous 2) Bolar 3) Cloggy 4) Compact 1) Argillaceous 2) Bolar 3) Compact and fine-grained 4) Covered or smeared with clay 5) Full of or abounding in clay 6) Like kaolin 7) Like or resembling clay 8) Like red soil 9) Like some earth 10) Like some soil 11) Like some soils 12) Mudlike 13) Resembling or containing clay 
• (a.) Consisting of clay; abounding with clay; partaking of clay; like clay.
Clay'ey adjective Consisting of clay; abounding with clay; partaking of clay; like clay. 
[adj] - (used of soil) compact and fine-grained
cloggy adjective (used of soil) compact and fine-grained; `the clayey soil was heavy and easily saturated`
covered or smeared with clay. · like or resembling clay. · full of or abounding in clay.