The microscopical examination which I have been compelled to make of so many hundreds of fossil insect-remains, for the most part in a fragmentary condition, from the Lower Plirhecks of Dorset, although beyond measure tedious from the unsatisfactory results afforded hy the nature of the specimens, has still enabled me to arrive at some results, and to form a general comparison of these insect-deposits with those which I similarly investigated whilst preparing the plates of Mr. P. B. Brodie's work on the fossil insects of the Wiltshire Purbecks, &c.