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139 slates, therefore, differ so much from the sandstones, that there can be no d )ubt. that the orisfin and source, fiom whet ce they were deiiveo, was different also. They indi- Ciite a total change in the direction in which the sediment can)e, .'ind as there is no formation to the northwest, or southwest, to which their oiigin can be attribnted, 1 am inclisied to reojard the source as concealed by the present' ocean The sandstones in the United States, of the ages closely approximating to those under consideration, were deposited ill shallow water. '1 he ripple marks, the foot prints, wvhich have been preserved, are regarded as proofs of this position. Taking the same ground and kind of evidence, I have not yet been able to furnish the same ground of proof for their deposi-tion in shallow water. I have not yet discovered footprint?, or ripple marks, and the only f^ict, which goes to support the view entertnined, of the depth of watev, in which the strata were deposited, is. a single laver, which had cracked in dry-ing. These cracks were subsequently filled with sediment. Still, but few opportunities for a disclosure of the inte-rior of these deposits have been furnished. The blocks of sand.-^toiie, which have b^-en employed in b\iildmg, h;ive been procured from the surface, and which were alreiidy loosened from their beds; besides this, the strata hiive not been laid nare by an inundation. The means, there-f( ire, lor ol)taining a series of facts, bearing upon these questions, aie ii;snflici( nt. They throw but little light U[)oii them, and we n)usi, tlierefore, wait until railroads and intt-rnil iuiprovemenis have 1 id open the series to in-spection. The evidence, as it now stands, favors the view, that these rocks were deposited in deep water ; the absence of all ripple marks, the great thickness d ihe deposits, and thickness of the deeper layers, indicate for the sandstones deep oceaaic deposits.
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Title | Page 535 |
Full Text | 139 slates, therefore, differ so much from the sandstones, that there can be no d )ubt. that the orisfin and source, fiom whet ce they were deiiveo, was different also. They indi- Ciite a total change in the direction in which the sediment can)e, .'ind as there is no formation to the northwest, or southwest, to which their oiigin can be attribnted, 1 am inclisied to reojard the source as concealed by the present' ocean The sandstones in the United States, of the ages closely approximating to those under consideration, were deposited ill shallow water. '1 he ripple marks, the foot prints, wvhich have been preserved, are regarded as proofs of this position. Taking the same ground and kind of evidence, I have not yet been able to furnish the same ground of proof for their deposi-tion in shallow water. I have not yet discovered footprint?, or ripple marks, and the only f^ict, which goes to support the view entertnined, of the depth of watev, in which the strata were deposited, is. a single laver, which had cracked in dry-ing. These cracks were subsequently filled with sediment. Still, but few opportunities for a disclosure of the inte-rior of these deposits have been furnished. The blocks of sand.-^toiie, which have b^-en employed in b\iildmg, h;ive been procured from the surface, and which were alreiidy loosened from their beds; besides this, the strata hiive not been laid nare by an inundation. The means, there-f( ire, lor ol)taining a series of facts, bearing upon these questions, aie ii;snflici( nt. They throw but little light U[)oii them, and we n)usi, tlierefore, wait until railroads and intt-rnil iuiprovemenis have 1 id open the series to in-spection. The evidence, as it now stands, favors the view, that these rocks were deposited in deep water ; the absence of all ripple marks, the great thickness d ihe deposits, and thickness of the deeper layers, indicate for the sandstones deep oceaaic deposits. |