This is a comic/novelty song in 6/8 time with music by Harry Gifford (who wrote for George Formby) and lyrics by Terry Sullivan. Introduced by Wilkie Bard, it is better known as a children's nursery rhyme, for which of course it has been adapted.
There are variants on the title, with or without a hyphen. Nursery rhyme or not, it is actually based on a real person who was a lot more than a mere shell seller. Mary Anning (1799-1847) who was born at Lyme Regis, made a precarious living searching for and selling fossils, but she also discovered the first ichthyosaur skeleton. In September 2010, she was recognized by the Royal Society as one of the most influential British women in science.
Alexander Baron - London, England