. The earth in past ages. Geology, Stratigraphic; Earth sciences. i6o THE STORY OF THE Fig. 3^—The base of Gal- sub-rotundus, showing the central po- sition of the mouth from the Upper Chalk. recognised, the material is amorphous and a product 6l decomposition of organisms. This may be evidence that a large part of the sub- stance of the chalk not only consists of the remains of animals which preserve their forms, but that the remain- der of it passed through the bodies of animals which have left little other record of then- existence. The fishes are the chief link between the
. The earth in past ages. Geology, Stratigraphic; Earth sciences. i6o THE STORY OF THE Fig. 3^—The base of Gal- sub-rotundus, showing the central po- sition of the mouth from the Upper Chalk. recognised, the material is amorphous and a product 6l decomposition of organisms. This may be evidence that a large part of the sub- stance of the chalk not only consists of the remains of animals which preserve their forms, but that the remain- der of it passed through the bodies of animals which have left little other record of then- existence. The fishes are the chief link between the Chalk and the Upper Greensand, a la;\ number of small sharks oi the two deposits being iden- tical. There is the greatest contract between the beds in mineral character; and in the principal types of fossils, because the Upper Greensand gives a record of conditions of the shore where sediment was accumulating; and the chalk gives evidence of conditions in the open almost beyond the limit to which, sediment was earned, thus demonstrating how great the difference in fossils may be with a slight interval m time. The conditions compared are such, in the two deposits, as may be found on the one hand on the SOUth-weSt shores of Ireland at the present day, and on the Other hand on the ocean floor 400 Or 500 miles to the west m the Atlantic, where an organic deposit is now accumulating which Closely resembles the chalk. But the sharks On the [rish COaSt are not limited to the shore, and leave their remains m the open OCeafl as well ; iiv as happened in the ages of the Upper ind and chalk. Just as sea-urchins occur. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Seeley, H. G. New York, Review of Reviews Co.
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