Editing Carboniferous (Namurian and Westphalian) of the Cliviger Valley, Todmorden - an excursion
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=== Locality 8 [SD 907 276] === | === Locality 8 [SD 907 276] === | ||
− | The third sandstone, the Holcombe Brook Grit, and its overlying shales, is rather better exposed. In many parts of this region this Grit is capped by a good-quality coal, one of the oldest hereabouts. However at this locality a cannel coal is developed, a much poorer quality shaly coal that is formed by the transport and deposition of vegetation in pools and ponds. The cannel coal sits on a | + | The third sandstone, the Holcombe Brook Grit, and its overlying shales, is rather better exposed. In many parts of this region this Grit is capped by a good-quality coal, one of the oldest hereabouts. However at this locality a cannel coal is developed, a much poorer quality shaly coal that is formed by the transport and deposition of vegetation in pools and ponds. The cannel coal sits on a seatearth containing curious lumpy concretions. |
− | Around 30 | + | Around 30 m downstream from the top bedding plane of the Holcombe Brook Grit, the Gastrioceras cancellatum Marine Band occurs at stream level. The fossils are rather poorly preserved at this locality. |
=== Locality 9 [SD 907 273] === | === Locality 9 [SD 907 273] === | ||
− | Further downstream, the Lower Haslingden Flags intersect the stream. Around 2 | + | Further downstream, the Lower Haslingden Flags intersect the stream. Around 2 m above the top of the sandstone a hard-weathering, fissile, black shale sits on a horizon of contorted shale. The appearance of this shale and its geochemical attributes are identical to that of marine band black shales; this is the newly discovered Owd Bett's Marine Band. It is named after a type locality north of Bury. The only marine fauna consists of rare conodont microfossils. More of these marine bands without goniatites probably await discovery in the Pennines. The Gastrioceras cumbriense Marine Band occurs a further 2 m above the Owd Bett's Marine Band at the top of the section ([[:File:YGS_YORKROCK_FIG_08_03.jpg|Figure 8.3]]). |
=== Locality 10 [SD 907 272] === | === Locality 10 [SD 907 272] === | ||
− | This splendid gorge in the Rough Rock allows nearly the entire 34 | + | This splendid gorge in the Rough Rock allows nearly the entire 34 m thickness of the sandstone to be examined. In the upper part of the section, cross sets up to 8 m in height can be discerned — testimony to the presence of large dunes or bars that must have formed in a channel of appreciable depth. |
== [[Yorkshire rocks and landscape: a field guide#Glossary|Glossary]] == | == [[Yorkshire rocks and landscape: a field guide#Glossary|Glossary]] == |