  We announce the classification of two related classes of flag-transitive
geometries. There is an infinite family of such geometries, related to the
nonsplit extensions $3^{[{n\atop 2}]_{_2}}\cdot \SP_{2n}(2)$, and twelve
sporadic examples coming from the simple groups $M_{22}$, $M_{23}$, $M_{24}$,
$He$, $Co_1$, $Co_2$, $J_4$, $BM$, $M$ and the nonsplit extensions $3\cdot
M_{22}$, $3^{23}\cdot Co_2$, and $3^{4371}\cdot BM$.
