16-TilliteSimilar to no. 15, but darker, and with fewer, smaller pebbles. This tillite was deposited by ancient glaciers in Canada about 2 billion years ago. Younger (250-million-year-old) Permian tillites from South America, Africa, India, Australia, and Antarctica have been used to correlate strata across the Atlantic and Pacific Oceans, giving evidence for seafloor spreading and "continental drift." Interestingly, this product of Precambrian glaciations was found in Pleistocene glacial deposits in the France Stone quarry. (Compare with no. 15, no. 17, and no. 18.) 
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