Meganeura is a genus of extinct insects from the Carboniferous period, which resembled and are related to the present day dragonflies. Meganeura were predatory, and fed on other insects, and even small amphibians. Carboniferous is the fifth period of the Paleozoic Era. It spanned from about 355-295 million years ago. The rocks that formed during this time interval are known as the Carboniferous System; they include a wide variety of sedimentary, igneous, and metamorphic rocks. The economic importance of the Carboniferous is evident in its name, which refers to coal, the important energy source that fueled the industrialization of northwestern Europe in the early 1800s and led to the Carboniferous being one of the first geologic systems to be studied in detail. The Pennsylvanian is, in the ICS geologic timescale, the younger of two sub-periods of the Carboniferous Period. It lasted from roughly 323-298 million years ago. The rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain by a few million years. The Pennsylvanian is named after the American state of Pennsylvania, where the coal productive beds of this age are widespread.