Crimsworth Dean
Also within
Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| SD988294 | — | Favourable | 0.86 | 2023-02-16 |
| SD990308 | — | Favourable | 1.28 | 2023-02-09 |
| SD992320 | — | Favourable | 0.73 | 2023-02-09 |
Habitats
Geology & landscape
Geological Period: Carboniferous
Description
Description A nationally important section exhibiting a sequence of rocks of the Namurian Kinderscoutian Stage, with a number of well developed marine bands present. The section is of considerable importance as it has been proposed as the stratotype for the upper part of the R1 Stagehighest Kinderscoutian and in conjunction with the River Darwen, provides a complete reference section for the entire Kinderscoutian time interval. In layman's terms, the interest of this site may be expressed more simply and such a statement is provided below. This should not be taken as definitive and further information as to details of the interest can be obtained from the Nature Conservancy Council. The bed and banks of Crimsworth Dean Beck provide exposures of a series of rock layers of the Namurian Series formed during the Carboniferous Period of geological history about 320 million years ago. The rocks consist mainly of shales and sandstones formed by the accumulation of sediment on a vast delta, built by a major river which flowed southwards from uplands in Scotland. Some of the shales contain the fossilised remains of marine animals which accumulated during periods when the delta became submerged beneath sea level. These marine layers are most important as they have enabled geologists to accurately date the rocks, making possible precise comparisons with rocks of similar age elsewhere in Britain and overseas. This river valley is recognised by geologists as a most important section and has been proposed as the standard or type locality for part of one of the major sub divisions of the Carboniferous Period, known as the Kinderscoutian Stage.
Plant communities
A9 — Fast flowing river and stream, Marginal and inundation, Pond ditch and canal, Sluggish river and stream
Potamogeton natans community
Show 20 indicator speciesSchoenoplectus lacustris, Juncus bulbosus, Sparganium angustifolium, Sparganium erectum, Sparganium minimum, Alisma plantago-aquatica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Elodea canadensis, Lemna minor, Lemna trisulca, Nymphaea alba, Callitriche platycarpa, Callitriche stagnalis, Littorella uniflora, Potamogeton natans, Ranunculus trichophyllus, Glyceria fluitans, Chara subspinosa
A14 — Fast flowing river and stream
Myriophyllum alterniflorum community
Show 15 indicator speciesIsolepis fluitans, Juncus bulbosus, Fontinalis antipyretica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Lemna minor, Callitriche stagnalis, Littorella uniflora, Potamogeton filiformis, Potamogeton gramineus, Potamogeton natans, Ranunculus peltatus, Chara spp., Nitella hyalina
A17 — Chalk river and stream, Fast flowing river and stream
Ranunculus penicillatus ssp. pseudofluitans community
Show 11 indicator speciesBerula erecta, Nasturtium officinale, Elodea canadensis, Lemna minor, Callitriche stagnalis, Veronica beccabunga, Polygonum amphibium, Polygonum hydropiper, Potamogeton crispus, Potamogeton pectinatus, Ranunculus penicillatus ssp. pseudofluitans
A18 — Fast flowing river and stream
Ranunculus fluitans community
Show 12 indicator speciesFontinalis antipyretica, Fontinalis squamosa var. curnowii, Myriophyllum alterniflorum, Myriophyllum spicatum, Elodea canadensis, Mentha aquatica, Lemna gibba, Lemna minor, Potamogeton perfoliatus, Ranunculus fluitans, Glyceria fluitans, Phalaris arundinacea