21. Eozoon canadense (1864)

Eozoon canadense

The Geological Survey of Canada’s Geology of Canada published in 1863 included William Logan’s account of the 1858 discovery near Ottawa of a piece of crystalline limestone whose structure and appearance suggested an organic origin. If correct, this sample would be a fossil of the earliest forms of life on Earth and a significant Canadian contribution to science. Similar samples were found in other locations in Laurentian rocks, which under the microscope showed apparent organic characteristics. The suggestion of an organic origin gained momentum, led by William Dawson, Principal of McGill University, who, in 1864, named the fossil Eozoon canadense (dawn animal of Canada).

Logan and Dawson reported their findings to the Geological Society of London that Eozoon canadense was a giant fossil foraminifera. The proposed organic origin was challenged with others arguing that the structures were of a mineralogical origin. This view was supported by the discovery of similar samples in rocks of many different ages and localities. Logan began to question his ideas, but Dawson remained unshakeable. The controversy continued until 1894 when identical structures were seen in metamorphosed limestone blocks ejected from an Italian volcano – clearly not an organic origin.

Category: Rocks, Fossils, Minerals and Meteorites

Decade: 1860s


Zeller, S., 2009. Inventing Canada: Early Victorian Science and the Idea of a Transcontinental Nation; Carleton Library Series 214; McGill-Queen’s University Press; 372 p. [reprint].

GSC 175 - CGC 175