Interval approximately 54 million years ( 542 - 488.3 million years old). Oldest time division of the Paleozoic Era. There were widespread seas and several scattered land masses. The largest continent was Gondwana. The average climate was probably was warmer than today, with less variation between regions. There were no land plants or animals, but marine organisms with either shells or skeletons. Because the dominant animals were trilobites. The Cambrian is sometimes referred to as “The age of Trilobites”