He is known for his studies of extinct marine invertebrates, especially the Brachiopoda and Ammonoidea of the Jurassic era (c. 201 – c. 145 Ma (million years ago)).

His major work, A Monograph of the Ammonites of the "Inferior Oolite Series" (never really completed), was published in several volumes by the Palaeontographical Society 1887-1907.

[7] In 1996, Peter Doyle wrote, "Buckman's original work involved a high degree of precision in collecting and measurement of stratigraphical sections which demonstrated the potential for the high-resolution scheme he later constructed.

Although Buckman's later excesses cast doubt on the accuracy of this work, detailed observations have shown it to be broadly correct and of great importance in long-distance correlation with North America, for example.

Clearly, the excesses of Buckman's later theorising have long held back an important contribution to detailed, high-resolution ammonite biostratigraphy".