117 



I am not, of my own knowledge, able to speak of the existence of 

 these fossils in Great Britain. They appear, however, from Lhwydd's 

 catalogue, to be by no means rare, in different parts of Gloucester- 

 shire, Oxfordshire, Northamptonshire, &c. 



It is exceedingly gratifying to me, to be able, through the kindness of 

 Mr. Meade, to place before you a representation of a beautiful minute 

 orthoceratite, brought by him from the Appennines, near Sienna. 

 Plate VIII. Fig. 16, is the fossil of its natural size ; and Fig. 17 is 

 the representation of the same fossil, magnified by a single lens, for 

 the purpose of obtaining a more distinct view of its structure. 



Colonel Montague, alluding to a recent, minute, straight, chambered 

 shell, varying in some respects from N. costatus, Linn, gives the follow- 

 ing description of this fossil, which I take the liberty of introducing, not 

 merely on account of its perspicuity and correctness, but because I could 

 not myself have subjected a sufficient number to real inspection, with- 

 out trespassing further than I wished on Mr. Meade's kindness. 



" A most elegant shell of this kind is found fossil upon the Appen- 

 nines, near Sienna, several of which we have been favoured with by 

 Mr. Meade and Mr. Higgin-sori. These vary a little; but the most per- 

 fect are an inch in length, completely cylindric, except at the last 

 joint, which is rather larger, and terminates conically, ending in a small 

 protuberance, nearly half as long as the joint to which it belongs: the 

 anterior end of those which appear perfect, is a little contracted round, 

 and smooth, or projecting beyond the ribs ; in the centre is placed the 

 aperture or syphon, whose margin is finely crenated. 



" They vary also as much in the number of chambers as in that of the 

 ribs; possessing from ten to fifteen of the former, and from nine to 

 twelve of the latter: the joints are not much raised, but usually two or 

 three at the anterior end more than the rest. The shell is extremely 

 thick in proportion ; and we found, by dividing several down the mid- 

 dle, that the septa were equally strong, and each furnished with a small 



