There is also a case for a fungal affinity for the enigmatic microfossil "Ornatifilum". The term "macrofossil" stands in opposition to the term microfossil. Olivooides is an extinct, sphere-shaped microfossil from Cambrian strata. All three types of microfossil morphologies are found in cherts. The fossils are primarily isolated teeth recovered from vertebrate microfossil sites. Hadrosaur eggshell fragments are however present in two microfossil sites in the area. To avoid confusion, microfossil assemblages were used to classify the chalk marl. Even microfossil data can be unreliable if there are hiatuses in the fossil record. Microfossils found in chert extend the Barberton microfossil record back to 3.5 billion years. A typical microfossil study will involve identification of a few hundred specimens from each sample.