ERA PERIOD AGE (of start) Cenozoic Quaternary 1.6 my Tertiary 65 my Mesozoic Cretaceous 140 my Jurassic 205 my Triassic 250 my Paleozoic Permian 290 my Carboniferous 355 my Devonian 410 my Silurian 438 my Ordovician 510 my Cambrian 540 my

Quaternary 1.6 million years ago - Today Life Dominant life includes: Mammals, humans First Homo Sapiens Climate The climate is relatively cool with ice at the poles. There were dramatic glaciers (permanent bodies of ice that move due to its heavy weight) that covered much of the continents, including much of the Lehigh Valley. Geology Continuation of weathering and erosion, forming the current landscape. The main rock types/ deposits in PA are silt, clay, gravel and sand.