INSECTS
shows no sign of weakening or of decrease in numbers. Of all the land animals, the insects are the true blue-blood aristocrats by length of pedigree.
The first remains of insects known are found in the upper beds of the rocks laid down in the geological period of the earth's history known as the Carboniferous. Dur-
Fig. 54. A group of common Carboniferous plants reaching the size and proportions of large trees. (From Chamberlin and Salisbury, drawn by Mildred Marvin from restorations of fossil specimens.) Courtesy of Henry Holt & Co.
Of the two large trees in the foreground, the one on the left is a Sigillaria, that on the right a Lepidodendron; of the two large central trees in the background the left is a Cordaites, the right a tree fern; the rail stalks in the outermost circle are Calamites, plants related to our horsetail ferns
ing Carboniferous times much of the land along the shores of inland seas or lakes was marshy and supported great forests from which our coal deposits have been formed. But the Carboniferous landscape would have had a strange and curious look to us, accustomed as we
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