Title On the Petrials of thin rank 3 geometries Authors D. Bonheure, F. Buekenhout, D. Leemans Reference J. Geom. 71(2001), no. 1-2, 19-26. Math. Reviews 2002g:51014 Zentralblatt 1013.51005 Abstract The aim of this paper is to extend the concept of a Petrial to thin (regular) rank three geometries. The main result is that if the Petrial of a thin regular residually connected geometry G is also a thin geometry, the geometry G has a linear diagram.