Crocs !

   Fossil discovery is often the result of chance and a large number of specimens kept in museum and university collections have been found by amateur, “lucky” collectors.Paleontologists do not search for fossils randomly; they usually concentrate their exploration on localized areas. How do they choose them? Paleontologists search for fossils where sedimentary rocks are exposed and thus easily accessible (quarries, mines, building excavations, deserts, sea cliffs, etc.). They first use geological maps to locate the appropriate rocks that may contain fossils. In order to find Mesozoic marine reptiles, for instance, paleontologists focus their research on marine sedimentary rocks of the Triassic, Jurassic or Cretaceous ages. Then the fieldwork entails prospecting for new localities. Fossil hunters patiently survey the sedimentary rock, inspecting fossil fragments exposed to the surface of the ground. Only after successful prospecting work will the fossil hunters start digging.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

     Sedimentary rocks are usually very hard, and scientists have to use appropriate instruments to dig. Most of the time, hammers, chisels, punches and trowels are much more helpful than brushes. Fossil hunting requires patience and tenacity. Scientific expeditions do not often lead to major discoveries: partial or complete skeletons are very rarely found. Geolocalization and the precise sedimentary succession in which fossils have been found are recorded in the field and are useful for further comparison. Once discovered, fossils need to be excavated. This is a delicate operation, as fossils are always very fragile. Most of the time, fossils are not entirely removed from the rock. The hunter carefully digs out the rock around the fossil so that part of the sediment pod encompassing the fossil is conserved. Bones are sometimes covered by tissue or paper before being enclosed in plaster. Once the plaster has dried, the fossil-bearing block is removed form the surrounding rock and brought to the laboratory for further preparation and cleaning by lab specialists.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

     Tiny fossil teeth, bones, or invertebrates are easy to remove and transport to the laboratory. Collecting and transporting large fossils such as bones of large mosasaurs require special skills. As fossil bones are considerably heavier than the original bone, package and transport with motor vehicles and in some cases aircrafts is often required for larger specimens. In the laboratory, the first step is to clean up the fossils and remove them from their surrounding protective plaster and rock matrix. Technicians and paleontologists then use a cleaning tool (engraver, awl, brush..) or chemical solutions (acetic or formic acid) to meticulously remove the whole matrix rock from fossils. Damaged fossils collected in several pieces are then reassembled. Finally, fragile fossils are consolidated with diluted glue or resin painted over them. The study of microfossils requires a microscopic observation, so micropaleontologists have to crush the rock sample with a mortar then apply part of the powder into a thin section to inspect it with a microscope. In all cases, cleaning and repairing fossils takes a long time and requires the special skills of professionals.