Geol. [SUB- 7 c.] A subdivision of a zone.
1888. A. Geikie, in Q. Jrnl. Geol. Soc., XLIV. 403. At the top of the fourth subzone … an interesting discovery was made of a thin band containing Serpulites.
1894. Geol. Mag., Oct., 442. Showing five sub-zones … with names of all the genera and species found in each.
