A HISTORY OF BUCKINGHAMSHIRE 



dinosaurian reptile from the Portland Limestone of Beagle Pit, Hart- 

 well near Aylesbury, which have been described by the present writer 1 

 under the name of Pelorosaurus humerocristatus. The genus Pe/orosaurus, 

 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 Pe/orosaurus, 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 Mega/osaurus, 

 whose remains were first discovered in the middle Jurassic strata of 

 Oxfordshire. These teeth have been described by Dr. Smith Woodward 2 

 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 chimsra-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 Golymbosaurus 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. 



Quart. Journ. Geol. Soc. xlix. 566. * Proc. Geol. Assoc, xiv. 31. 



