Subject ASC000128o
The Quarterly journal of the Geological Society of London.
v.67 (1911), Page 421 (1845)
Smithsonian Libraries
BHL Page 39749303
Keywords
landscape geologic section stratigraphy Montgomeryshire wales geology Gwern-y-brain section limestone shale Cloddian beds' Powis-Castle shales Gaerfawr Grits Gwern-y-brain Group rocks observations fossils A Wade cross-section geologic map sedimentary layers stratification drift fault quarry bedding conglomerate sandstone fossiliferous calcareous volcanic strike-fault Section gwern-y-brain ordovician rocks strata Rock/stone layers cloddiau trilobite-dingle powis-castle