File:The Quarterly journal of the Geological Society of London (1881) (14747692506).jpg

Identifier: quarterlyjourna371881geol (find matches)
Title: The Quarterly journal of the Geological Society of London
Year: 1845 (1840s)
Authors: Geological Society of London
Subjects: Geology
Publisher: London (etc.)
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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te typenext underlie the grits of the country east of Lampeter. By anexceptional appearance the Metalliferous slates of the west seem tounderlie the Aberaeron grits. No pale slates are seen beneath theTalieris conglomerate beds. The principal axial fold in the sectionseems to be a synclinal in the Teifi valley by Lampeter—themountains to the east and west of this being (that is, if the rock-dips have any truth in them) great anticlinals in the Metalliferous -slate and Ehyader Pale-slate series. The beds of grit and con-glomerate at Talieris are not of the nature of basement beds of astratigraphical group, but indicate nothing more than such slightphysical variations as a shallowing of the sea-bed or a change in thedirection of the currents, resulting in the formation of sand andpebble banks ; for the pebbles are not fragments of the underlyingrocks, and there is no trace of any physical break or even change oflithological character above and below them, GEOLOGY OF CENTRAL WALES. 150
Text Appearing After Image:
WALTER KEEPING ON THE be ? I- 1 (3) ffliyader to the Teifi Pools(fig. 5).—In this section threemain folds are indicated, namely acentral anticlinal fold at Disgwylfain the Ehyader pale slates, with asynclinal on its east and west.The former is a comparativelysimple basin of pale slates beneaththe grits and conglomerates ofCwm Elan and Gwastaden; thelatter, corresponding with thePlynlimmon synclinal, is a muchmore complicated structure, pro-bably much affected by reversals. General Result of the East andWest Traverses (see fig. 6).—Thesections just indicated show thatthe great area of Mid Wales ismade up of a thick series of im-perfect slates, pale slates, shalesand grits, having a general re-semblance and intimate connexionthroughout, as of one continuousgroup, but divisible into the sub-groups indicated in the beginningof this paper. These rocks form one great pri-mary synclinal extending from theAberystwyth axis to the east ofEhyader, and from the west ofLlandeilo to Aberaeron.

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