54 



On the occurrence of Ancyloceras Annulatus in Dorsetshire. By 

 LocKHAET Kennedy, Esq. Communicated hy Peofessoe 

 BUCKMAN, F.A.S., &c. 



As the occurrence of tliis form of Cephalopoda in so old a rock 

 as the Inferior Oolite is a matter of some geological interest, it 

 is to be hoped that a few remarks upon some specimens found 

 at Bradford Abbas will be of interest to the Cotteswold Club. 



The genus Ancyloceras, though nearly allied to the Ammonite 

 in many important particulars, is yet separated from it by the 

 fact that whilst in the Ammonite the whorls are in contact, and 

 even generally overlapping, the Ancyloceras has, as it were, the 

 whorls uncoiled. 



The greater number of species of this group belong to the 

 chalk series. In the Oohtes we have, in the Inferior OoHte, the 

 specimens under review ; also, in the Lower Oxford Clay are two 

 species mentioned by d'OEBiGNY as 



1. Ancyloceras Calloviensis, Morris 



2. Ancyloceras distans 



Of these the first was formerly called Crioceras, to which genus 

 aU of them have been referred. 



Our Dorsetshire specimen is weU figured by D'Oebignt under 

 the name of Ancyloceras annulatus, the specific character depend- 

 ing upon some prominent annular ribs. The author refers to 

 the following synonyms : — 



Hamites annulatus, Deschayes 



Toxoceras obliquus, Baugier cmd Jav/zi 



Ancyloceras costatus, Morris 



"Waltoni, Morris 



It occurs sparingly in this district, in a thin band of coarse 

 rubbly OoKte, which we may perhaps say is made so by the 

 quantity of fossils which it contains. The bed itself is about 



