Dictionary of National Biography, 1885-1900/Dennis, James Blatch Piggott

DENNIS, JAMES BLATCH PIGGOTT (1816–1861), histologist, son of Philip Piggott Dennis, an officer in the army, took the degree of B.A. at Queen's College, Oxford, and was ordained in 1839. He is best known by his microscopical investigations into the internal structure of bone, of which he gave an account in the papers published in the ‘Journal of Microscopical Science.’ He is credited with having established two important geological facts, namely the existence of mammifers anterior to the lias deposit, and the existence of birds during the deposition of the Stonesfield slate, or further back by many formations than had been previously known (Journ. Microsc. Sci. iv. 261, v. 63, 191). The results of his researches were welcomed by men of high scientific rank, such as Professor Owen and Professor Henslow, and on the proposal of Owen he was elected a member of the Geological Society. The mammal jawbone which Dennis had discovered fourteen years previously in the Stonesfield slate formed the subject of a paper which Owen read before this society (Geol. Soc. Journ. xiii. 1–11). In connection with Dennis's discovery of the Stonesfield slate it is related that the curator of one of the university museums having sent some perfect bones to Professor Owen, and a few minute fragments of the same parcel to Dennis, the two investigators, without communicating with each other, both arrived at the same conclusion and ascribed the bones to the same fossil reptile. In 1860 Dennis read a paper before the British Association ‘On the Mode of Flight of the Sterodactyles of the Coprolite bed near Cambridge’ (Brit. Assoc. Rep. 1860, p. 76). Besides contributing papers to the ‘Journal of Microscopical Science’ and other serials, Dennis was the author of various pamphlets on theological and scientific subjects. He died on 13 Jan. 1861 at Bury St. Edmunds.

[Annual Register; Ipswich Journal, 19 Jan. 1861; Ward's Men of the Reign; Royal Society's Catalogue of Scientific Papers, ii. 239, iv. 727.]

R. H.