Possibly Leptoceratops gracilis, the “small horned face” was discovered in Western North America and described by Barnum Brown in 1914.
Leptoceratops lived during the Late Cretaceous in the late Maastrichtian. It was 1.8 meters (6.9ft) in length, 0.8 meters (2.6ft) in height at the hips and 150 pounds (68kg) in weight. Leptoceratops material has been collected in St. Mary River Formation (Montana), Canada; Lance Formation (Wyoming), Hell Creek Formation (Montana), United States. Leptoceratops lived in the late Maastrichtian, the late Cretaceous. It is known from the Scollard Formation(Alberta) Canada;Lance Formation(Wyoming), Hell Creek Formation(Montana), United States. It was a basal ceratopsian and belongs to the family Leptoceratopsidae. It may have sportted long quill like knobs on its tail.
Leptoceratops is a basal Ceratopsian, more basal then Protoceratops. Leptoceratops and Montanaceratops form the Leptoceratopsidae. Leptoceratops probably lived in woodlands, or forested areas.
This unknown Marginocephalian can be found on Isla Sorna. The evidence for this animal to be on Isla Sorna is a logo in The Making of The Lost World: JP Movie Book and The Dinosaurs of The Lost World & Jurassic Park Scrapbook, this leaves it to be in question to be on Isla Sorna. Due to this, the unknown Marginocephalian is debatable and based on visual identification as being on Isla Sorna due to the logos mentioned. We’re not entirely sure that it is a Leptoceratops that the logo is representing but it is a likely candidate though. Worthy of note is that there were talks of Leptoceratops prior to the movie’s release, and it actually was in a prior script before one of the final revisions before TLW’s filming. However, this script is now lost to us. A coin collection, from The Lost World: Jurassic Park merchandising, shows the only other known logo for this animal. However, this logo is accompanied by text referring to the creature as Pachycephalosaurus. This is suspect as the animal looks nothing like the creature it’s supposedly representing. For now, however, the dinosaur is most likely Leptoceratops but is still considered an uncertainty. For all we know it could even be Microceratus.