Precambrian Cobalt Ontario

Coleman's mapping in Northern Ontario led him in 1906 to announce, to a startled world of geology, that he had discovered glacial deposits in the Precambrian of Cobalt, Ontario. He later recalled,

[I] had been impressed with ... [the Huronian slate conglomerates’] glacial appearance for several years before final proofs were obtained that they were the work of ice . The evidence turned up first in the Cobalt silver mining region of Ontario, ... [The] opening of the silver mines gave excellent exposures of the conglomerate .
. . . ice action has been proved or shown to be probable in the Keweenawan, the Anirnikie, the Huronian, the Timiskaming and the Keewatin, i.e., in all of the main subdivisions recognized in Canada, where the largest area of Precambrian rocks in the world is exposed. In the case of the Huronian (Cobalt or Gowganda) the area of glaciation is so great that one must assume a very important refrigeration, one to be classed among the first four in severity. ... The finding of these evidences of ancient glaciation has revolutionized our ideas as to the origin and history of the world ...

"Glaciation in Huronian Times, "Ice Ages Recent and Ancient (New York: Macmillan, 1926): 220 and 239 - 240