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The Carboniferous was the age of lycopods and amphibians, as the Devonian had been the age of rhizocarps and fishes. The upridging of the Appalachians had begun and a wide continental uplift proved by the absence of Permian deposits over large areas where sedimentation had gone on before opened new lands for settlement to hordes of air-breathing animals.
By May 15 we were off the southern tip of the Grand Banks of Newfoundland. These banks are the result of marine sedimentation, an extensive accumulation of organic waste brought either from the equator by the Gulf Stream's current, or from the North Pole by the countercurrent of cold water that skirts the American coast. Here, too, erratically drifting chunks collect from the ice breakup.
This is usually done by adding an excess of chloride of lime, which precipitates the soap as a curd and carries the dirt down with it. By sedimentation, and filtration through canvas, cinders and sand, the water is clarified and turned into the creeks again clean. So completely can this be accomplished that the experience at one bath house is worth narrating.
Graded by this and that species, the debris is reduced to fine particles, which upon sedimentation help to raise the level of the reef and thus prepare foundations for dry land.
From data afforded by the eruptions in Java and in other fields where the quantity of volcanic dust contributed to the seas can be estimated, the writer is disposed to believe that the average rate of sedimentation on the sea floors is twice as great as the estimate above given.
The processes of oxidation and carbonation are also expansive processes. Whether any of this gain in volume is lost in the process of sedimentation and reconsolidation, I do not know. Probably all the elements that water takes from the rocks by solution, it returns to them when the disintegrated parts, in the form of sediment in the sea, is again converted into strata.
The great laboratory in which the sedimentary deposits are accumulated, the realm in which at least ninety-nine of the hundred parts of these materials are laid down, is the oceanic part of the earth. On the floors of the seas and oceans we have not only the region where the greater part of the sedimentation is effected, but that in which the work assumes the greatest variety.
This constant passage of the mineral elements of the rocks through the cycle of erosion, sedimentation, and reinduration has exposed them to the action of the air, the light, the sea, and has thus undoubtedly brought about a steady growth in their volume and a constant change in their color and texture.
How do the Triassic sandstones and shales compare in hardness with the igneous and metamorphic rocks about them? The Jurassic strata are wanting over the Triassic areas and over all of eastern North America. Was this region land or sea, an area of erosion or sedimentation, during the Jurassic period?
All that will be necessary in the spring will be to rake or harrow the ground. The clods will crumble. I once had occasion to try this method upon about 25 acres of land which had been made by pumping mud from a river bottom upon a marsh thus converted into dry ground by the sedimentation. Three sturdy horses were needed to do the plowing. The earth turned up in chunks as large as a man's body.
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