On the Niimmulite Limestone of Alabama. 187 



which constitute the chief part in bulk, of considerable masses 

 of limestone in certain districts. Having obtained many speci- 

 mens both from Alabama and from Vicksburg in Mississippi, in 

 which the structure of this fossil was beautifully preserved, 1 first 

 showed them to Prof. E. Forbes, who at once pronounced them 

 not to be Nummulites, but related to some living plants or zoo- 



Mr 



Mr 



dale, who examined them immediately afterwards, said, " They 

 are certainly not Nummulites, but allied to some of the bodies 

 usually termed Orbitolitcs, and are I believe corals in the usual 

 acceptation of that word." Afterwards Mr. Forbes having com- 

 pared the American fossil with the living species from Australia 

 and satisfied himself of its near affinity, sent me the following 

 note, dated June 14th, 1847. " On the so-called ' Nummulites 

 Mantelli.' The American Nummulites Mantelli, judging from 

 Mr. Lyell's specimen, is not a Nummulite nor is it a foraminife- 

 rous shell. It is a species of Orhitolites and consequently a zoo- 

 phyte, (probably Ascidian. ) The genus Orhitolites was estab- 

 lished by Lamarck for the reception of a fossil of the Paris basin, 

 the Orhitolites complanata, which may be regarded as the type. 

 Other tertiary species and a Maestricht fossil, were associated by 

 Lamarck in the same genus, in which he also placed the ' Orhitoli- 

 tes marginalise of the European seas. Respecting the true posi- 

 tion of the last-named body, however, there is considerable doubt.'" 



The Orhitolites complanata is very nearly allied to the Ameri- 

 can fossil. The Orhitolites elliptica of Michelin, from near Nice, 

 and that author's Orhitolites Pratti, are also closely allied species. 



In British strata, species of Orhitolites are recorded from the 

 greensand of Milber down, from the chal k of Lewes, and from 

 Jhe coralline crag of Sutton. It is possible however that bodies 

 belonging to distinct genera have been placed together in our lists. 



Mr. Jukes has collected at Swan river, in Australia, numerous 

 disciform bodies, apparently Ascidian zoophytes, which occur 



? 



—ww ui great numoers upon marine piuuts icowu«»"& ~ •> 



and when dead are found in great abundance in mud, procured 

 by *h.e dredge from various depths under seventeen fathoms. 

 These disks are usually about half an inch m diameter and are 

 composed of minute cells. Thev appear to me to belong to th. 

 sanie generic group with the tertiary Orhitolites, and such ap- 

 pears also to have been the opinion of Defiance, for we can 

 f freely doubt that these are the bodies alluded to by him (in the 

 following passage) as living in the seas of New Holland : «Uj W 

 e *I*ce" (i. e . Orhitolites complanata of the Paris basin) a e 

 P ],1 s grands rapports avec celle que l'on trouve vivant dans les 

 jfrs de la Nouvelle Hollande."* Margiuopora ot Uuoy and 

 "aimard seems to be a similar body. 



» Diet. des. Sc. Nat., p. :!G, Art. Orbitolitet. 



