On the Plant-Remains from the Downtonian of England and Wales
On the Plant-Remains from the Downtonian of England and Wales
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DOI：
10.1098/rstb.1937.0004
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发表时间：
1937-06
期刊：
影响因子：
--
通讯作者：
W. H. Lang
中科院分区：
文献类型：
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作者：
W. H. Lang
本文中描述的植物遗迹所源自的地层是 W. Wickham King 先生所使用的唐顿阶术语的扩展含义。因此，它们不仅包括拉德洛骨床、唐顿砂岩和特梅赛德页岩（即灰色唐顿阶），还包括厚度大得多的红色泥灰岩和砂岩，这些红色泥灰岩和砂岩以前被归为下老红砂岩，但现在被称为红色唐顿阶。这种看待地平线岩石的方式已经根据 O.T. Jones (1929, pp. 110-121) 的观点历史进行了充分讨论，在此无需进一步考虑。这些地层在不同时期被包含在志留纪或老红砂岩中。这里没有必要讨论志留纪和泥盆纪之间的最佳界限问题。可以参考 Stamp (1923)、O.T. Jones (1929) 和 Wickham King 最近的论文 (1934)。出于植物研究的目的，只要认识到唐顿阶地层位于更明确的海相卢德洛夫岩石上方和更明确的下老红砂岩大陆床下方就足够了。格雷唐顿庄园的过渡性质早已被接受，并且可以很容易地扩展到威克姆金唐顿庄园中包含的后续床位。
The strata from which the plant-remains to be described in this paper are derived are those which are grouped as Downtonian in the extended sense of this term employed by Mr. W. Wickham King. They therefore include not only the Ludlow Bone-bed, the Downton Sandstone, and the Temeside Shales, i.e ., the Grey Downtonian, but a much greater thickness of red marls and sandstones that were formerly classed with the Lower Old Red Sandstone, but are now spoken of as the Red Downtonian. This way of regarding the rocks of this horizon has been fully discussed in the light of the history of opinions by O. T. Jones (1929, pp. 110- 121) and need not be considered further here. These strata have been included at different times in the Silurian or in the Old Red Sandstone. It is not necessary here to enter into the question as to the best limit between the Silurian and the Devonian. Reference may be made to Stamp (1923), O. T. Jones (1929), and to Wickham King’s recent paper (1934). It is sufficient for the purposes of this study of the plants to recognize that the Downtonian strata come above the more definitely marine Ludlovian rocks and below the more definitely continental beds of the Lower Old Red Sandstone. The transitional nature of the Grey Downtonian has long been accepted and can readily be extended to the succeeding beds included in the Downtonian by Wickham King.