sulcation

Noun

 * 1) A channel or furrow.
 * 2) Markings resembling channels or furrows, especially in shells, fossils, etc.
 * 3) * 1865, (ed.), Memoirs of the Geological Survey of India, Volume 1, page 8 (Google preview):
 * The ornamentation of the shell is a character of considerable palaeontological importance. . . . The types of ornamentation are two; longitudinal striation, and transverse sulcation conformable to the shape of the aperture.
 * 1) * 1946, Charles W. Gilmore, "Reptilian Fauna of the North Horn Formation of Central Utah", Professional Paper 210-C, U.S. Dept. of the Interior, p. 45 (Google preview):
 * [T]he presence of sulcation in the brow horns of all the Arrhinoceratops specimens known at the present time suggests a certain constancy in this genus.
 * 1)  The development of or resulting formations of sulci in a brain cortex.