Carboniferous period (360-290 million years ago) This period spanned within a time interval of from 360 million to 290 million years before present. The word Carboniferous derived from English and it means coaly sediments, which were formed in this period. Black or coaly sediments could be found in Northern Europe, Asia , Middle East and Northern America . Carboniferous is a geological time period using worldwide. This period is divided to two parts; Mississippian (Lower Carboniferous) and Pennsylvanian (Upper Carboniferous). These are also geological time periods used only in North American geology. This coordinated system is used for Pennsylvanian coal layers made of Mississippian coral rocks and their result is different in stratigraphy and various facies. Carboniferous forests of this period are known via their huge coaly swamps. As these swamps have produced coal, the name of Carboniferous is used for them. In addition to appropriate conditions for coal production, fundamental biological and geographical events occurred in this period of time. The first vertebrates living on land were carnivores. Whereas, leaves and plants were insects' food. Most of jaws'insects were specialized for fruits and plants'seeds consumption. Some of the others have a kind of small trunk for drinking plant nectars. Giant dragons bearing length of more than 60cm were flying among tall trees. Flying insects developed till the end of this period. Different types of spiders were living within Carboniferous. A group of centipede bearing a length of more than 105cm was recognized at the end of this period. Reptiles and the first herbivore vertebrates appeared at the end of this period. At that time weather was dry and significant changes occurred in herbivores.