ألف توماس عدة مؤلفات ما بين 1830 و1860 من أبرزها: كتاب تنين البحر العظيم (The book of the great sea-dragons, Ichthyosauri and Plesiosauri, taninim gedolim taninim, of Moses.
The two best known are "Memoirs of Icthyosaurii and Plesiosaurii" (1835) and "The Book of the Great Sea Dragons" - full title "The book of the great sea-dragons, Ichthyosauri and Plesiosauri, taninim gedolim taninim, of Moses.