When this new age of the world opened, we find that there was plenty of life, and that there were many creatures akin to some that we have living to-day. To enjoy that time of the world we should have been no longer Afrites, or flame-spirits, for the reign of the fire was over; we should have been Pixies, and able to wander at our will among the plants and animals in the water. There we should have noticed that there were many animals of the articulate or jointed class--creatures that have no backbones; and we should have seen that the plants were sea-weeds of various kinds. As the ages of this great time moved on, creatures with vertebræ forming backbones appeared, and the land had vegetation. There were reeds, rushes, lichens, ferns, mosses, plants of the toad-stool kind, and great trees such as are now not found on the earth. Some of the rushes called calamites were larger than the great bamboo. The first age of this great time is called the Cambrian, from the outcrop of its rocks in North Wales, the ancient Cambria. The name Huronian has also been applied to it, as these rocks largely appear in the region about Lake Huron. In this age new land rose above the ocean. The waters were still warm, and the atmosphere was hazy and full of moisture, hot, but without clear sunlight. The animals were corals and crabs; the vegetables were sea-weeds. The rocks of the Cambrian are chiefly sandstone and slate, and we find the fossils not scattered through all the rocks, but in layers, so that some ledges of rock are nearly destitute of organic remains, and then come others crowded with fossils of animals and vegetables. Among the earliest and most curious of the fossils are the lingulæ. These are bivalve[9] shells, about the size and shape of your finger-nail. The lingula was fastened to the sand bed by a fleshy stem. Opening its valves, it put forth a fine fringe which served it as fingers for gathering its food from the waters, much as barnacles do.[10] The lingulæ belong to the group of lamp shells, and have existed through all the ages from the Cambrian until now, as they swarm at the present day in the China seas. Along with the busy little lingulæ lived many varieties of crabs, cuttle-fish, star-fish, and many kinds of corals. Probably there were not many insects in this period: only a few fossils of large insects somewhat like dragon-flies and May-flies have been found. There were no birds, and the great forests of reeds and club-mosses were silent, unless the few insects could produce a chirping sound. Possibly their wings and bodies were gaily colored as those of the dragon-flies are to-day.