Also known as the Leeds Hippopotamus.
On 3rd April 1832 employees of Messrs Longley were digging in clay deposits west of Wellington Road in New Wortley, Wortley, West Yorkshire, to collect clay for making brick when they discovered unusual bones.  The site is now in Armley, Leeds and is shown on the 1854 Ordnance Survey map as a brickfield west of Wellington Road, in New Wortley.  Part of the site is now beneath the roundabout known as Armley Gyratory. Henry Denny, the curator of the Leeds Philosophical and Literary Society museum, identified the bones as those of the Great Northern Hippopotamus. Denny visited the clay deposit where he found bones from hippopotami, an elephant and an auroch.  The hippopotamus bones became known to the scientific community as the Wortley Hippopotamus or the Leeds Hippopotomus. For more than a century the bones were undated, with debate over whether they were of the Eemian (Ipswichian) or last interglacial period, or else were an import made in historic times (see history) and buried. In 1976 a report was printed on radiocarbon dating on a Wortley Hippopotamus bone.  This gave a mid-Devensian or last glacial period dating, but a further assay was carried out on a molar (tooth) which produced an interglacial period dating. The bones are held at the Leeds Museum Discovery Centre. 
- Denny, H: "On the Discovery of Hippopotamic and other Remains in the Neighbourhood of Leeds", ' 'Proceedings of the Yorkshire Geological Society' '.
- "The Leeds Hippo", ' 'BBC Leeds' ', September 2004.
- DD Harkness, GD Gaunt, JH Nunney: "Radiocarbon dating versus the Leeds Hippopotamus—a cautionary tale", ' 'Proceedings of the Yorkshire Geological Society' ', 1976 .