Geometric style Kraters such as this one were used as grave markers.  This krater illustrates prothesis or the laying out of the dead for a funeral.  Large kraters such as these are usually around 40 inches tall and have a hole in the bottom.  The hole would allow liquid offerings for the dead to flow into the earth.  This type of vessel was replaced as a grave marker by stone monuments in the 6th century B.C.
photo from the Metropolitan Museum of Art

photo by Mary Harrsch (cc-at-nc-sa)