Dictionary:

arenaceous

  (ăr'ə-nā'shəs)

1. Resembling, derived from, or containing sand.
2. Growing in sandy areas.

[From Latin harēnāceus, arēnāceus : harēna, arēna, sand; see arena + -āceus, –aceous.]

Sandy in texture, or applied to rocks composed of cemented, usually quartz, sand. Arenaceous rocks include quartzites and greywackes.

Composed primarily of sand; sandy.

The adjective has one meaning:

Meaning #1: resembling or containing sand; or growing in sandy areas
  Synonyms: sandy, sandlike
  Antonym: argillaceous (meaning #1)