Warm seas probably covered the Westmorland Dales during parts of the Jurassic and Cretaceous, which between them spanned an expanse of time lasting from 200 to 65 million years ago. Any rocks that did form here during those periods have long since eroded away and we need to visit places such as the Yorkshire coast to see Jurassic and Cretaceous rocks and fossils.
A Jurassic ammonite from Whitby on the Yorkshire coast. © E. Pickett
Jurassic ammonites preserved as the mineral pyrite at Ravenscar on the Yorkshire coast. cc-by-sa/2.0 - © Andrew Curtis - geograph.org.uk/p/1474095
Cliffs of Cretaceous chalk at Flamborough Head on the Yorkshire coast. cc-by-sa/2.0 - © Pauline E - geograph.org.uk/p/2894580