of AcanthophoUs horridus. 69 



remains of Ichthyosaurus campylodon and Saurocephalus lanciformis 

 occurred in the same bed, numerous teeth of both genera being 

 found. Many well-marked species of Cephalopoda, peculiar to this 

 lower zone of the Chalk Marl, occur in the same matrix^ viz., 

 Ammonites Bothomagensis, Brong. ; Am. navicular is, Mant Am. 

 Mantelli, Sow. ; and Am. varians, Sow. ; which last species has a 

 wider range in time and space than the other three. The nonin- 

 voluted sinistral Ammonitidce, represented by Turrilites costatus, Lam.; 

 T. tuberculatus, D'Orb. ; T. undulatus, Sow. (^Scheuchzerianus Bosc); and 

 Scaphites ceqaalis, occur plentifully, accompanied by Nautilus elegans, 

 Sow, and N. pseudoelegans, D'Orb ; Terebratulina striata, Schloth. 

 (rigida, Sow.), Terehratula biplicata, Broch. ; T. obesa. Sow., were 

 the only species noticed as coming from that particular horizon, 

 Fleurotomaria perspectiva, Mant. ; P. rhodani, Brong., the latter 

 peculiar to the Lower Chalk, occurs but sparingly, and chiefly 

 in the form of casts. The associated bivalves of the group Asiphonida, 

 are Ostrcea carinata, Sow. ; Plicatula inflata, Sow. ; P.pectinoides, Sow. ; 

 Inoceramus mytiloides, Mant. ; Exogyra, Pecten orbicularis, Sow., and 

 casts of other species ; and only one genus of the Siphonida, viz., 

 Pholadomya decussata, was observed amongst them. Of the Eehino- 

 dermata fragments of Goniaster Coombii or G. mosaicus, Forbes ; Pel- 

 tastes clathrata, Aq. ; P. umbrella, Aq. ; Discoidea subucula, Klein ; 

 Holaster subglobosus, Leske ; Pseudodiadema {JDiadema) resembling 

 variolare, but eroded ; and an Hemiaster ; also club-shaped spines of 

 Cidaris. All these species occur in the Chalk Marl along the 

 shore, and are obtainable from fallen masses. Several Amorphozoa, 

 such as Chenendopora fungiformis , Brachiolithes labrosus, and another 

 species, are plentiful in places. This singular genus of Ventriculites 

 forms the chief mass of the lower part of the bed in which the Eep- 

 tilian remains occur. Vermicularia is the only annelide noticed. 



The above organic remains were found associated with Acanthc • 

 pholis in the same matrix, and they tend not only to elucidate the 

 contemporaneous or co-existing fauna, but also to give exactness to the 

 determination of its age. Whether the habits of AcanthophoUs 

 resembled the Scelidosaurus of the Lias, or the Hylceosaurus, and 

 Iguanodon of the Wealden, future research may more definitely 

 determiue. We cannot, however, fail to notice that in this new 

 form another link is added to the persistency of type preserved 

 through so long a period of time, and through those numerous 

 geological changes which occurred during the deposition and 

 succession of the lower, middle, and upper oolitic rocks, as well 

 as the Wealden and Cretaceous formations. It is to be regretted 

 that the skeleton should have been so dismembered, but the 

 unyielding nature of the matrix, which is tough, much jointed, 

 and possesses that conchoidal fracture peculiar to hard marly de- 

 posits, rendered it almost impossible to remove it in any other way 

 than piece by piece, and it was so incorporated with the remains, 

 that none but an experienced workman could have succeeded in 

 relieving even so much as is preserved to us. 



