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Dawson (1820–1899), Principal of McGill University and a giant in the history of North American geology. Schooled chiefly in Edinburgh, Scotland, the son of strict Scottish Presbyterians, Dawson was a staunch Calvinist and devout antievolutionist (O'Brien, 1971).

In 1858, a year before publication of Darwin's opus, specimens of distinctively green- and white-layered limestone collected along the Ottawa River to the west of Montreal were brought to the attention of William E. Logan, Director of the Geological Survey of Canada. Because the samples were known to be ancient (from “Laurentian” strata, now dated at about 1,100 million years) and exhibited layering that Logan supposed too regular to be purely inorganic (Fig. 1), he displayed them as possible “pre-Cambrian fossils” at various scientific conferences, where they elicited spirited discussion but gained little acceptance as remnants of early life.

In 1864, however, Logan brought specimens to Dawson who not only confirmed their biologic origin but identified them as fossilized shells of giant foraminiferans, huge oversized versions of tiny calcareous protozoal tests. So convinced was Dawson of their biologic origin that a year later, in 1865, he formally named the putative fossils Eozoon canadense, the “dawn animal of Canada.” Dawson's interpretation was questioned almost immediately (King and Rowney, 1866), the opening shot of a fractious debate that raged on until 1894 when specimens of Eozoon were found near Mt. Vesuvius and shown to be geologically young ejected blocks of limestone, their “fossil-like” appearance the result of inorganic alteration and veining by the green metamorphic mineral serpentine (O'Brien, 1970).

FIGURE 1. Eozoon canadense, the “dawn animal of Canada,” as illustrated in Dawson's The Dawn of Life (Dawson, 1875), (A) and shown by the holotype specimen archived in the U.S. National Museum of Natural History, Washington, DC (B). (Bars = 1 cm.).



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