Analysis reveals a wealth of shallow-water marine species, some in life position, along with trace fossils including Rhizocorallium burrows well exposed at Old Nab, east of Staithes.

[5] Immediately beneath the Raisdale Seam at Staithes can be seen laminated beds with basal gutters up to 1 foot 8 inches (0.5 m) wide and 16 feet (5 m) long which were scoured out during high energy storm events.

These features tend to be oriented in an east-west direction and are fairly persistent laterally, occurring almost 12 miles (19 km) to the south-east at Hawsker Bottoms.

They reside within the upper part of the Amaltheus margaritatus faunal zone[9] and are collectively referred to as the Penny Nab Member, after a headland c.150 metres east of Staithes Harbour.

[11] Ancillary components include calcite (as MgCO3 and MnCO3), pyrite (FeS2), collophanite (Ca3P2O8 H2O ), silica (Si), clay minerals and derivatives such as octahedrite (brookite) (TiO2), and dickite (Al2Si2O5(OH)4).

The ooids (on average) comprise ~33% siderite, ~33% berthierine, and a similar proportion of ancillary minerals and demonstrate deformation whilst the sediment was still plastic.

Evidence of bivalves in life position, Rhizocorallium trace fossils, cross-bedding, episodes of non-deposition and (not least) the oolitic texture all indicate that the ironstones were laid down in shallow water.

Economically, the Cleveland Ironstone proved to be a crucial catalyst with the power to reinvigorate the flagging commercial fortunes of the River Tees and surrounding district.

[15] Vaughan and Marley's evidence of a large scale body of workable iron ore in close proximity to both coal and limestone from County Durham, together with the district's developing communications network by rail and sea, proved a heady concoction.