Morley's initial investigation of the site mostly focused on the hieroglyphic inscriptions; after that Uaxactun was not visited again until 1924, when Frans Blom made a more detailed investigation of the structures and mapped the site. The Carnegie Institution conducted archeological excavations there from 1926 through 1937, led by Oliver Ricketson. The excavations added greatly to knowledge of the early Classic and pre-Classic Maya. The remains of several badly ruined late Classic era temple-pyramids were removed, revealing well-preserved earlier temples underneath them.