This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1910 Excerpt: ...Devonian known as the Pilton group in North Devon becomes sandstone. In Cornwall these rocks are represented by limestones and slates at Petherwyn. The striking feature of these rocks is the remarkable change which takes place in the marine life. The multitude of genera which had survived m.ore or less conspicuously ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1910 Excerpt: ...Devonian known as the Pilton group in North Devon becomes sandstone. In Cornwall these rocks are represented by limestones and slates at Petherwyn. The striking feature of these rocks is the remarkable change which takes place in the marine life. The multitude of genera which had survived m.ore or less conspicuously from the Cambrian to the Silurian time becomes replaced by new sets of types which are substantially the same as survive through the marine beds of the carboniferous period. Some layers are characterized by a few peculiar genera, such as the continental deposits in the Middle Devonian known from the Brachiopod Stringoccphalus, as Stringocephalus limestone; and from the coral Calceola as Calceola slate, which give a distinctive character to the Devonian period. It is in the Devonian age that we are particularly impressed with the abundance on the earth of types of life which enter largely into the existing fauna. Fishes have hitherto been few in number, but some of those remarkable fishes Pterichthys which occurred at the top of the Ludlow beds, together with Coccosteus and the great scaled fringe-finned Holoptychius, are found in the marine Devonian beds of the continent, as well as in the old red sandstone of Scotland. In this period commence several marine univalve shells such as Natica, Nerita, Trochus, Vermetus, which are so important in the sea-shore life of the present day. They are associated with two very interesting Cephalopods. Nautilus occurs accompanied by the remarkable Nautiloid shell named Clymenia, which has a fold in each septum which divides one chamber from another, similar to the fold which is observed in the septa of many tertiary species of Nautilus, which are similarly compressed from side to side. Those compressed tertiar...
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Seller's Description:
Very good; Collectible. Stored copy very clean from estate of book collector. No names or marks. NO SUN-DAMAGE. GOLD LETTERING ON SPINE. DATED 1909. ALMOST NO WEAR TO COVER. EXCEPTIONAL CONDITION. 04 12 2009 HIST-102 022.
