This study of the deformation of fossils due to tectonic activities is the first study to be carried out in Jordan. The different stress fields that produced folding, stylolization and reverse flexuring, are believed to have also produced the deformation of the fossils. Folding, stylolization and reverse flexures are structures, which can unambiguously be referred to defined stress fields. The deformation directions of the fossils are in this study correlated to the structures having unambiguous stress field producing them. The correlation was very clear and accordingly therefore, deformed fossils can be used as very good indicators on the stress fields which produced them irrespective, whether these stress fields have left any macrostructures in the rocks which indicate at them or not.