Hordle Cliff Unio Bed, Hampshire (Eocene of the United Kingdom)

Also known as Hordwell

Where: England, United Kingdom (50.7° N, 1.6° W: paleocoordinates 49.2° N, 5.5° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Headon Beds Formation, Late/Upper Eocene (37.2 - 33.9 Ma)

• The Unio bed lies between the Rodent bed (above) and a green clay unit (below), as described by Cray, 1973. The Marchioness herself describes it as "Stratum 3"

• bed-level stratigraphic resolution

Environment/lithology: shelly/skeletal, gray, yellow claystone and lignite

• A lilac or gray clay with bands of buff. Very narrow bands of lignite traverse this bed; the thickest occurs about 4 or 5 incles above its base. Its chief characteristics are the layers of U. solandri which begin about 4 in. from the top, and to on increasing in numbers to nearly the end of the bed.

Size class: macrofossils

Collection methods: In 1852, the Marchioness of Hastings published an almost identical paper to her 1853 report. I used the later English version, but the earlier paper is the more primary reference.

Primary reference: M. Hastings. 1853. On the Tertiary Beds of Hordwell, Hampshire. Philosophical Magazine and Journal of Science, Fourth Series 6(36):1-11 [J. Alroy/E. Leckey/E. Leckey]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 39828: authorized by John Alroy, entered by Erin Leckey on 07.06.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

• Normally, Gardner et al.s' inclusion of M. turritissima would be a re-id of the Marchioness's M. polygyra, but her identifications seem to be more careful than theirs, and I think it's more likely that the latter ID is incorrect or that they have an additional sp. than that she was wrong.
 Unionida - Unionidae
Unio solandri freshwater mussel
Unio nuttalli n. sp.2 freshwater mussel
 Architaenioglossa - Viviparidae
 Sorbeoconcha - Thiaridae
"Melania polygyra" = Thiara, "Melania turritissima" = Thiara1
"Melania polygyra" = Thiara snail
"Melania turritissima" = Thiara1 snail