It is most commonly known from the late Campanian of Alberta and Montana, but specimens have also been found dating to the older Santonian and the younger Maastrichtian.

Its microstructure is very similar to that of theropods; it differs from avian eggs in its relative size, its lack of a third eggshell layer, and its prominent ornamentation.

[10] One Continuoolithus egg contains embryonic remains representing a relatively early stage of development so that the skeleton was almost entirely cartilaginous, which has been largely replaced in the fossil by an amorphous calcite mass.

The taxonomic identity of the embryo is impossible to determine, but based on comparisons to Troodon, Orodromeus, and Maiasaura, it is estimated to have been 60–70 mm (2.4–2.8 in) long.

It clearly represents a very early stage of development (in fact, it is the youngest vertebrate skeleton ever discovered), both because of the lack of ossification and because of its tiny size relative to the egg; based on comparisons to the developmental patterns of modern birds, Horner (1997) estimated it may have died eight to ten days after fertilization.

[3] Continuoolithus canadensis has one junior synonym, Spongioolithus hirschi, which was originally classified as a distinct oogenus and oospecies of Elongatoolithidae.

In 1990, Continuoolithus specimens, found at the Egg Mountain locality, were first described in detail by paleontologists Karl Hirsch and Betty Quinn, but they did not give them a parataxonomic name.

At that time, prominent American paleontologist Jack Horner believed them to be eggs of Troodon based on the appearance of the embryonic remains.

It was not prepared and described until 2012, when Rebecca Joy Schaff analyzed this nest and other Continuoolithus specimens extensively in her masters thesis at Montana State University.

[2] In 2008, Ed Welsh and Julia Sankey published the first report of fossil dinosaur eggs from Texas, discovered in the Aguja Formation.

[5] In 2017, a team of Canadian paleontologists led by Darla Zelenitsky reported the discovery of a pair of Continuoolithus shell fragments at the Willow Creek Formation in Alberta, representing the first fossils of the oogenus found in the Maastrichtian.

[6] The same year, Zelenitsky et al. also discovered the first Continuoolithus specimens in the Santonian, found at the Milk River Formation, also in Alberta.

[7] The oogenus and oospecies Spongioolithus hirschi was first named in 1999 by Emily Bray, based on numerous eggshell fragments discovered at the North Horn Formation.

[23] The formation has a diverse assemblage of dinosaurs including theropods such as Troodon, Albertosaurus, ornithomimids and dromaeosaurs, as well as several types of hadrosaurs, ceratopsians, ankylosaurs, and smaller ornithischians such as Orodromeus.

[22] The formation was also populated by multituberculate mammals,[30] numerous types of turtles, Champsosaurus, sturgeons, and pterosaurs (including the giant Quetzalcoatlus).

[22] It is widely known for its incredible diversity of dinosaurian fauna, representing over 50 valid taxa including theropods such as dromaeosaurs, caenagnathids, troodontids, ornithomimids, and tyrannosaurids, as well as ornithischians such as pachycephalosaurs, hadrosaurs, ceratopsians, ankylosaurs, and thescelosaurs.

[9] Other Continuoolithus specimens, not classified into an oospecies, are known from the late Campanian of the Fruitland Formation (representing a well-drained river delta plain) in New Mexico, along with Porituberoolithus, Prismatoolithus, indeterminate theropod eggshells, Testudoolithus, and krokolithids.

canadensis fragments were also found in the late Santonian Milk River Formation, wlong with Porituberoolithus, Prismatoolithus, Spheroolithus, and Triprismatoolithus.