In 1949 she worked on Grahame Clark's excavations at the Star CarrMesolithic site in Yorkshire.
Around the same time she began studying the Langdale axe industry in Cumbria, the project for which she is perhaps best remembered.[1] She was not the first person to notice that Neolithic axes had been produced in Great Langdale, but she was able to demonstrate the scale of the activity there, and used the word "factory" to describe it. She also guessed correctly that other quarries would be found on outcrops of volcanic tuff in the Lake District.
Fell kept up to date with scientific advances and collaborated with Winifred Pennington in the study of the effects of humans on the environment, resulting in pioneering pollen analyses for prehistoric artefact layers from sites in Cumbria.[citation needed]