1931-1962（昭和6-37）年に東京帝国大学、東京大学理学部の教員であった小林貞一教授の蔵書印と推測される。
蔵書印主についての文献：松本達郎. 小林貞一先生を悼む. 化石. 1996, 60, p.59-62. https://doi.org/10.14825/kaseki.60.0_59, (参照 2022-8-22).
典拠資料：Seward, A. C. The Wealden flora. pt. 1: Thallophyta-Pteridophyta. British museum, 1894, xxxviii, 179p., (Catalogue of the Mesozoic Plants in the department of Geology British Museum Natural History, pt. 1). 資料ID:1011520549
https://opac.dl.itc.u-tokyo.ac.jp/opac/opac_link/bibid/2003196098
典拠資料：Seward, A. C. The Wealden flora. pt. 2: Gymnospermae. British museum, 1895, viii, 259p., (Catalogue of the Mesozoic Plants in the department of Geology British Museum Natural History, pt. 2). 資料ID:1011520556
典拠資料：Seward, A. C. The Jurassic flora. pt. 1: The Yorkshire coast. British museum, 1900, xii, 341p., (Catalogue of the Mesozoic Plants in the department of Geology British Museum Natural History, pt. 3). 資料ID:1050242377
典拠資料：Seward, A. C. The Jurassic flora. pt. 2: Liassic and oolitic floras of England (excluding the inferior oolite plants of the Yorkshire coast). British museum, 1904, xii, 341p., (Catalogue of the Mesozoic Plants in the department of Geology British Museum Natural History, pt. 3). 資料ID:1050242385
https://opac.dl.itc.u-tokyo.ac.jp/opac/opac_link/bibid/2003196104
典拠資料：Lindley, John; Hutton, William. The fossil flora of Great Britain: or, figures and descriptions of the vegetable remains found in a fossil state in this country. v. 2, v. 3. J. Ridgway, 1833-37. 資料ID:1050253960, 1050253978
https://opac.dl.itc.u-tokyo.ac.jp/opac/opac_link/bibid/2003208445
色：朱
陰陽：陽
形状：正方形
印影外郭：単郭
印文文字数：6
印文改行表記：小林／貞一／文庫
Color：Vermilion
Pos./Neg.：Pos.
Form：Square
Outer frame：Single frame
Text length：6
Text with line breaks：小林／貞一／文庫