Mosasaur
Mosasaurs (from Latin "Mosa" meaning the 'Meuse river', and Greek σαύρος "sauros" meaning 'lizard') are an extinct group of large marine reptiles containing 38 genera in total. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. Mosasaurs probably evolved from an extinct group of aquatic lizards known as aigialosaurs in the Early Cretaceous. During the last 20 million years of the Cretaceous period (Turonian-Maastrichtian ages), with the extinction of the ichthyosaurs and pliosaurs, mosasaurs became the dominant marine predators. They became extinct as a result of the K-Pg event at the end of the Cretaceous period, about 66 million years ago.
Paleontology in Connecticut
In 1818, Solomon Ellsworth Jr. was blasting a well in East Windsor and uncovered some fossil bones about 18 feet under the surface of the rock. These are the first scientifically verified dinosaur bones discovered in North America. Two years later, Nathan Smith reported the fossils Ellsworth discovered to the "American Journal of Science", interpreting the fossils as human remains. In 1823 Professor Edward Hitchcock published research on Connecticut's fossil plants. In 1848 he wrote about the local tracks. By 1858, 38 different dinosaur track-bearing quarries were known in Connecticut but few additional finds would be made until the 1960s.