The Victoria History of the County of Buckinghamshire/Paleontology
PALÆONTOLOGY
SO far at least as published records go, Buckinghamshire seems to be exceedingly poor in vertebrate fossils, the only specimens of any real interest being a few teeth of dinosaurian reptiles and certain remains of fishes from the Purbeck and Portland strata of Aylesbury and its neighbourhood.
From certain Pleistocene deposits at Fenny Stratford the British Museum possesses two imperfect molar teeth and a tusk of the mammoth (Elepbas primige nius), which were presented by Sir Philip Duncombe in 1873.[1] And the occurrence of these specimens suggests that careful search would bring to light remains of other of the contemporary mammals in the neighbourhood. Teeth of the wild boar (Sus scrofa ferus) have indeed been dredged from the bed of the Ouse at NewportPagnell.
From coprolite-pits in the Cambridge Greensand near Puttenham remains of three species of vertebrates, commonly met with in that formation in Cambridgeshire, have been recorded by Mr. JukesBrowne.[2] These, according to modern nomenclature, are Ichthyosaurus campylodon, one of the extinct ' fish-lizards '; Protosphyrcena ferox, a large fish with spear-like teeth; and Lamna appendiculata a widelyspread species of Cretaceous shark. Ichthyosaurus campylodon is likewise said to have been obtained from the Chalkmarl of Waddon.
The Lower Greensand coprolite-beds at Rushmoor yield vertebrate fossils, derived chiefly from the Kimeridge Clay, similar to those found at Potton in Bedfordshire, but no list of the species seems to have been published, and no great interest attaches to the occurrence of the remains in question. Lower down in the geological scale the Purbeck beds of Aylesbury have yielded part of the lower dentition of a fossil fish belonging to the group of pycnodont ganoids which Dr. Smith Woodward[3] has made the type of a distinct species, under the name of Athrodon intermedius. This unique specimen is in the British Museum. Other remains in the same collection from the Purbeck of Hartwell and Bishopstone indicate a very different type of ganoid fish belonging to the widely-spread Jurassic genus Pleuropholis; the name P. serrata[4] has been proposed for the Buckinghamshire species.
Of wider interest are the crowns of two teeth of a gigantic dinosaurian reptile from the Portland Limestone of Beagle Pit, Hart- well near Aylesbury, which have been described by the present writer [5] under the name of Pelorosaurus humerocristatus. The genus Pelorosaurus, it may be observed, was founded on the evidence of a huge bone (humerus) of the fore-limb from the Wealden of Sussex. And since American specimens have shown that reptiles allied to this genus possessed teeth of the type of those from Hartwell it is a fair infer- ence that the latter belong to Pelorosaurus, although not to the same species as the one indicated by the Wealden humerus. Three other teeth from the same locality and formation belong to another and very different type of dinosaurian reptile, namely the carnivorous Megalosaurus, whose remains were first discovered in the middle Jurassic strata of Oxfordshire. These teeth have been described by Dr. Smith Woodward [6] without being specifically determined. A long-necked plesiosaurian reptile, Cimoliosaurus portlandicus, has left its remains in the Portland formation of Quainton ; the Buckinghamshire specimens having been originally described under the name of Plesiosaurus carinatus. Ichthyo- saurian remains are also reported, although not described, from Hartwell.
The Kimeridge Clay of the county has apparently hitherto yielded very few vertebrate remains. A fish-spine from this formation at Hartwell has however been assigned to the common Jurassic type known as Asteracanthus ornatissimus, which may belong either to a shark or to a chimaera-like fish. From the same locality have been obtained remains of the great short-necked and large-headed plesiosaurian known as Pliosaurus macromerus, the teeth of which are characterized by their triangular crowns.
The British Museum possesses a limb bone of a plesiosaurian, or long-necked marine saurian, from the Kimeridge Clay of Newport Pagnell, which is assigned to Colymbosaurus trochanterius, a species widely distributed in the formation in question. Among the fish-lizards the species Ichthyosaurus thyreospondylus is represented in the county by a bone obtained from the Oxford or Kimeridge Clay near Buckingham.
From the Great Oolite of Buckingham and Stony Stratford Pro- fessor J. Phillips records (Geology of Oxford) remains assigned to the great dinosaurian reptile commonly known as Cetiosaurus oxoniensis, but of which the proper title is probably Cardiodon rugulosus.