Nearly all the beds of this formation are marine, but there are associated with these the remains of a forest or old land surface, and a considerable accumulation of estuarine or fresh-water deposits; impure coals also occur in this formation.
"Geology"
James Geikie
Some members, however, of the series have an estuarine character, and must have been formed within the influence of rivers.
"The Student's Elements of Geology"
Sir Charles Lyell
Mr. John Buchanan, a zealous antiquary, writing in 1855, informs us that in the course of the eighty years preceding that date, no less than seventeen canoes had been dug out of this estuarine silt, and that he had personally inspected a large number of them before they were exhumed.
"The Antiquity of Man"
Charles Lyell