In consequence of this imperfect record we can not, as yet, trace a gradual successive growth from the low forms of animal and plant life, that characterized the closing period of Archean time, to the highly organized types of the present. The record suddenly ceases and when we again pick up the thread we are surrounded by more advanced types, higher forms of life. Though we may hope that future discoveries will do much toward completing the records, we can not hope that they will ever really be perfected. So, from our present stand-point, the history of life on the globe falls naturally into three great divisions.6 This is no more than we might expect, when we reflect that nature’s laws are universal in their action, and that the world, as a whole, has been subjected to the same set of changes. The period following on after Archean time is called, by geologists, Paleozoic time. During the long course of time embraced in this age, the forms of life present wide differences from those of existing time. This period produced the great beds of coal we use to-day. But the vegetation of the coal period would present strange features to our eyes. The vegetation commenced with the lowest orders of flowerless plants, such as sea-weeds; but, before it was brought to a close, there was a wonderful variety and richness of plants of the flowerless or Cryptogamic division. In some of the warmest portions of the globe, we have to-day tree-ferns growing four or five feet high. During the closing part of the Paleozoic time, there were growing all over the temperate zone great tree-ferns thirty feet or so in height. Some varieties of rushes in our marshes, a foot or two in height, had representatives in the marshes of the coal period standing thirty feet high, and having woody trunks.7 Near the close of the Paleozoic time, vegetation assumed a higher form of life. Flowering plants are represented. Pines were growing in the coal measures. In animal life a similar advance is noted. The class of animals having no backbone, or invertebrate animals, were largely represented. But, toward the close of the Paleozoic time, we meet with representatives of the backbone family. The waters swarmed with fishes.8 Besides these, there were amphibians; 9 and reptiles in the closing portions.10 The Pterodactyl