Oogenus: Preprismatoolithus ZELENITSKY & HILLS, 1996
Etymology: Latin, meaning before, in reference to the occurrence of Preprismatoolithus in the late Jurassic, prior to the late Cretaceous oogenus Prismatoolithus.
= Prismatoolithus HIRSCH, 1994

Oospecies: coloradensis (HIRSCH, 1994) ZELENITSKY & HILLS, 1996
= Prismatoolithus coloradensis HIRSCH, 1994

Holotype: MWC 122.3.1/HEC 457

Locality: Young Locality, Delta County, Colorado.

Horizon: Upper Salt Water Wash Member, Morrison Formation.

Biostratigraphy: Zone 2.

Age: Comobluffian age, Kimmeridgian Stage, uppermost Malm Epoch, Late Jurassic.

Material: Compressed egg.

Referred material:

MWC 122.2/HEC 418, 489, 532, 462, MWC 122.3/HEC 457, MWC 122.6, MWC 122.8: Four plaster jackets with eggs and eggshells.

MWC 122.1/HEC 418: Thousands of eggshell fragments.

MWC 122.2.3/HEC 418: The largest cast yielded among other eggshell conCenterations.

MWC 122.3/HEC 457: Egg.

MWC 122.2/HEC 418-R2, 532-4: Pathological eggshells.