Throughout history, the climate of Connecticut and the life it has supported have changed. This is quite evident in the types of fossils found here.
Most of the bedrock in Connecticut is either igneous or metamorphic in origin, except for the valley. When Pangaea was breaking up and our state was drifting toward its present position, a rift valley formed at the breaking point. Upon this valley, sand and other sediments washed down from the highlands. These sediments became the sandstones and shales, collectively known as the New Haven arkose and are the oldest fossil-bearing rocks in Connecticut. (Farrand, 1990)
Dinosaurs exited around the time this arkose was forming (Triassic Period), but none have been found in this rock. What has been found was a fossil reptile called
, which resembled a crocodile. Its bones have been found in Simsbury, showing that it attained a length of ten or more feet.
was a carnivore, feeding on fishes and other aquatic animals found in the swamps where it lived. (Farrand, 1990)
, another Triassic reptile has been found near the Quinnipiac River in Fair Haven. It was covered with armor plates and looked similar to an armadillo. (Farrand, 1990)
Fossils also give clues to past climates. The New Haven arkose contains imprints of leaves, bark and wood that tells us that in Mesozoic times, Connecticut had a tropical climate. Plants found included; conifers, horsetails, giant club mosses and cycads. (Farrand, 1990)
Students may not have heard of these plants and pictures do not do them justice. Horsetails and club mosses, while not as large as their ancestors are still native to Connecticut. They are interesting plants and should be shown in the classroom. If you can not find them growing in the wild, then a local garden shop or florist may be helpful. Horsetails (aka.
) are sometimes used as greenery in floral arrangements. Around the december holiday season, a roping called Princess Pine is sold. This is really a club moss. Cycads, are native to places such as Florida, but three species are sold as houseplants. They are called; the cardboard palm, sago palm or just cycads. Cycads are very unusual plants and I would recommend them highly for classroom use. They also make very hardy houseplants.
Further climatic evidence can be found pollen and spores preserved in Mesozoic lake sediments. By dissolving the 180 million year old shale in acid, these microscopic structures can be studied. From these, twenty-seven genera have been found, showing conifers as the major plants. This also shows that our climate at the time consisted of wet and dry seasons, with between 4-20 inches of rainfall per year. Further climatic evidence, was our location during the Mesozoic—ten degrees north of the equator. (Little, 1986) While dinosaurs roamed Connecticut, fewer then one hundred bones have been found, due to oxidation and decay. (Little, 1986) During the Jurassic Period, the Connecticut Valley contained many shallow and temporary lakes, with alot of mudflats. This is where the main evidence for dinosaurs is found—footprints. In 1966, a bulldozer accidentally uncovered the largest dinosaur trackway ever found in North America, in Rocky Hill, Connecticut. More than 2000 footprints, around 185 million years old were uncovered. (Farrand, 1990)
This trackway has become part of Dinosaur State Park, The park has on display about five hundred of these footprints. It is undergoing a renovation and by next spring will have an expanded display area, included within this will be other life that existed in Connecticut as well. In addition, the park will become more handicap accessible. (Brescia, 1995)
These tracks come from a dinosaur named
, most likely related to Tyrannosaurus. Its tracks range from about eight inches to three feet.
is thought to be from 10 to 50 feet in length. It is thought that
could swim and may have hunted in groups. Dr. John Ostrom, of Yale University tracked 19 pairs of
footprints. These footprints were all heading in the same direction, across a sandstone layer near the Connecticut River. (Little, 1985)
In Durham, Connecticut I have found a couple of
footprints in an old stream bed. My students are fascinated by them and it takes close to an hour for them to be passed around the room. I have also found fish fossils at two different sites in the Connecticut Valley, in shale beds. These fossils have been carbonized and are somewhat unusual.
Other fossils found in our state include fish coprolites (fossil feces) and invertebrate trails and burrows. (Little, 1986)