Question:  The Bowland Shale Formation is a Carboniferous geological formation of Asbian (Visean) to Yeadonian (Bashkirian) age, it is an organic-rich shale which, according to which organization, and is the source rock where "oil and gas matured before migration to conventional fields in the East Midlands and the Irish Sea"?
Sentence (from "East Midlands Oil Province"): The largest field in the province is the Welton oil field, the second largest onshore oil field in the UK.
Relevant evidence: No