[ ŏn′kə-līt′ ]
A stromatolite that is spherical rather than dome-shaped. Oncolites usually form around a nucleus consisting of a detrital fragment (such as a shell fragment or a grain of sand) and are less than 10 cm (3.9 inches) in diameter.
Words nearby oncolite
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.