The collection of manuscripts left by Strickland on his premature death cover the entire range of his interests, i.e. geology, ornithology, zoological nomenclature, zoological references, growth of seeds and the Ray Society. The contents of the volumes are briefly listed as follows:
- Volume with Manuscripts of Talks, Papers and Extracts. This includes a 'Plan of rendering the nomenclature of zoology uniform and permanent'. There are also copies of private letters to his parents written from Asia Minor in 1835.
- Volume with various manuscripts, including 'A week in Ireland', 'On the Geology of the Country between Worcester and London' and 'On altering names in nomenclature.'
- Two further volumes with about 50 manuscripts of talks and papers.
- Volume with title 'Travelling Collector and Ornithological Memoranda.' This has about 50 separate documents.
- Volume on 'Ornithological Nomenclature', with a Draft of the rules of nomenclature.
- Manuscript for the 'Biblioteca Zoologica'
- Volume with different catalogues of birds.
- Volume with a large variety of manuscripts.
- Volume on 'Experiments on the Growth and Vitality of Seeds' 1841-1853
- Volume with documents and letters relating to the Ray Society founded in 1844.
- Slip Catalogue with notes on birds.
- Volumes with correspondence and manuscripts relating to birds and nomenclature.