Some Salient Points in the Science of the EarthDawson, John William, Sir
Science
Some Salient Points in the Science of the Earth
Dawson, John William, Sir
Geology; Paleontology
Between 1860 and 1870 the writer was engaged in working out all that
could be learned of the Devonian plants of Eastern America, the oldest
known flora of any richness, and which consists almost exclusively of
gigantic, and to us grotesque, representatives of the Club mosses,
Ferns, and Mare's-tails, with some trees allied to the Cycads and
Pines. In this pursuit nearly all the more important localities were
visited, and access was had to the large collections of Professor Hall
and Professor Newberry in New York and Ohio, as well as to those of
the Geological Survey of Canada, and to those made in the remarkable
plant-bearing beds of St. John, New Brunswick, by Messrs. Matthew
and Hartt. In the progress of these researches, which developed an
unexpectedly rich assemblage of species, the northern origin of this
old flora seemed to be established by its earlier culmination in the
north-east, in connection with the growth of the American land to the
southward, which took place after the great Upper Silurian subsidence,
by elevations which began in the north, while those portions of the
continent to the south-west still remained under the sea.
When, in 1870, the labours of those ten years were brought before the
Royal Society of London, in the Bakerian Lecture of that year, and in a
memoir illustrating no less than one hundred and twenty-five species of
plants older than the great Carboniferous system, these deductions were
stated in connection with the conclusions of Hall, Logan, and Dana,
as to the distributions of sediment along the north-east side of the
American continent, and the anticipation was hazarded that the oldest
Palæozoic floras would be discovered to the north of Newfoundland.
Mention was also made of the apparent earlier and more copious birth of
the Devonian flora in America than in Europe, a fact which is itself
connected with the greater northward extension of this continent.
Unfortunately the memoir containing these results was not published by
the Royal Society, and its publication was secured in a less perfect
form only in the reports of the Geological Survey of Canada. The part
of the memoir relating to Canadian fossil plants, with a portion of the
theoretical deductions, was published in a report issued in 1871.[89]
In this report the following language was used:--
[89] "Fossil Plants of the Devonian and Upper Silurian Formations of
Canada," pp. 92, twenty plates. Montreal, 1871.
Public-domain text, read in full here on John Shaqi.
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