[UP- 7. Cf. prec.] Something that serves to fill up.
1822. G. Young, Geol. Surv., 168. The red sandstone … occupying the valleys in the form of what has been called an upfilling.
1833–4. Encycl. Metrop., VI. 705/2. At length the originally rugged chasm is changed by additions and upfillings into the smooth, evenly declining hollow.
1844. Stephens, Bk. Farm, III. 810. A gate to be permanent, should be … a simple rectangular frame without upfillings.
