The tongue twister is often attributed to the memory of the amateur paleontologist Mary Anning, but the best I can tell there is no connection.

In several versions of the story the song is ascribed to Terry Sullivan in 1908, but there are records of the phrase "she sells sea sells" in the mid-to-late 19th century, chiefly in 'elocutionary manuals'. And the song that putatively describes her life...just doesn't. The additional stanzas are about the humor of performing such a difficult tongue twister, and make no allusions to paleontology.

There are really quite a few imagined narratives and just-so stories with early paleontological figures. I'm not quite sure why myths like this develop (this blog explores the folklore of that tongue twister much better than I could), but they're pervasive - Thomas Jefferson, Lamarck, and (of course) Darwin are the greatest offenders. But that's not to say Mary Anning wasn't a foundational figure.

Anning is chiefly remembered for collecting ichthyosaur and plesiosaurs which were described with the geologist Henry De la Beche; these discoveries are important historically for supporting Cuvieran catastrophism as well as early steps toward understanding macroevolutionary trends. She herself was regarded as an apt geologist and paleontologist, but did not publish; she was neither formally educated nor from a wealthy background. She actually sold the fossils she collected, from quite common ammonites up to the ichthyosaur skeletons, which is particularly interesting when considering the origination of paleontology as a scientific discipline and the more recent relationships between commercial and academic paleontologists (Sue comes to mind!).

At any rate, while Anning is worth learning about, the tongue twister appears unrelated.