Theodore Henderson | Akateeminen Kirjakauppa

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: Reprinted from University of Colorado Siudies, Vol. Ill, No. 3, Boulder, Colo., June, 1906. THE FOSSIL FAUNA AND FLORA OF THE FLORISSANT (COLORADO) SHALES By T. D. A. Cockerell The Tertiary lake basin of Florissant, Colo., is one of the most famous localities for fossils in the world. The plants and insects of a past age are wonderfully preserved in fine volcanic sand or ash, deposited in layers which readily split apart, revealing the specimens, just as they fell, in prodigious numbers. Green leaves and even branch- lets were torn from the trees, and insects perished wholesale, in a catastrophe which must have equaled that of Martinique. There were, in fact, several successive eruptions, as about a dozen different horizons are found to be fossiliferous. While some of these may represent a single period of volcanic activity, it is not to be doubted that considerable periods elapsed between some of the deposits. Perhaps the non- fossiliferous shales were deposited so -soon after the fossiliferous ones that no living creatures remained to be entombed, all having been destroyed or driven away; in this case the next fossil-bearing layer will indicate a new eruption, following after a greater or less lapse of time. In all eleven vertebrates, one mollusc, 610 insects, 30 spiders, and about 145 recognizable plants have been described from these beds. The insects were all described by Mr. S. H. Scudder, except a few plant-lice named by Mr. Buckton from drawings supplied by Mr. Scudder, and some hymenoptera recently examined by the present writer. The Scudder collection, at the Museum of Comparative Zoology, Cambridge, Mass., contains probably at least another 400 species of insects. These were to have been described by Mr. Scudder, but he is no longer able to work upon them, ...