Page:The Habitat of the Eurypterida.djvu/65

 found in the Upper Old Red Sandstone of Ireland and England associated with land-plants (Archaeopteris, Sphenopteris, Bothrodendron, Ulodendron, Stigmaria, Calamites), fishes (Coccosteus) and arthropods (Eurypterus)" (74, 1003, 1004).

Steinmann in his Einführung in die Palæontologie merely states that: "These remarkable Crustacea reaching a length of 2 meters appear in the Cambrian and Silurian in association with marine animals, in the Devonian they live with the armor-plated fishes in the Old Red, in the Carboniferous and Permic they are found in fresh-water" (266, 373) Haug speaks of the salt and gypsum deposits of New York as lagoon formations, and includes here also the eurypterid beds at the end of the Siluric, thus reaching the same conclusion that many American authors have come to (112, 626)

Walther in the chapter entitled Das Aufblühen der Tierstämme in Silur in the Geschichte der Erde und des Lebens has accepted the statement of several American geologists that the eurypterids were marine organisms saying that they lived in sea-water of normal salinity "as the section in North America proves with certainty" (294, 251). The reference cited for this proof is Sarle's paper on the fauna from the Salina of Western New York. The significance of this occurrence will be discussed below, but we may say at this point that this instance seems hardly to furnish proof positive of a marine habitat. He also calls attention to the restriction of the eurypterids to the black shales, and of the absence of marine forms in association with the merostomes. He notes that in synchronous formations the eurypterids are found only in isolated localities. "Thus is the upper Silurian of Pennsylvania devoid of Eurypterus for a thickness of 500 meters" (294, 251). Walther's explanation of the isolated occurrences seems hardly to accord with the facts. He assumes that the regions devoid of eurypterid remains were great salty lakes cut off from the sea in which the eurypterids are supposed to have lived.

Ernst Stromer in the Lehrbuch der Palaeozoologie has added