G. C. Crick — On Nautilus rohiistus. 



343 



other specimen bears an original label with the inscription "Nautilus, 

 Marlstone. Gretton."^ Fully agreeing with Mr. Buckman's identi- 

 fication of these specimens, I was led to enquire into the geological 

 age of the examples in the National Collection, for if the Cheltenham 

 College specimens are correctly identified, it would seem that the 

 species belongs to the Marlstone or Middle Lias, rather than to either 

 the Upper Lias or to the Inferior Oolite. 





Nautilus robustus. — a, lateral view, showing the cast of part of the body-chamber, 

 the test being present in the septate part of the shell, where a few Hnea of 

 growth are indicated ; b, fi'ont view. Middle Lias : Les Moutiers, Normandy, 

 France. Drawn from the type - specimen in the British Museum collection 

 [No. 37,010]. Rather less than one-third natural size. 



As already stated, one of the examples on which the species was 

 founded, viz., the specimen in the British Museum bearing the 

 register number C. 1,944, lacks any information respecting the 

 horizon and locality whence it was obtained. Its matrix, however, 

 agrees with that of the specimen in the Cheltenham College Museum 

 that is labelled " Marlstone. Loc : unknown ; but probably near 

 Cheltenham, and possibly Alderton Hill." It is therefore more than 

 probable that this fossil is a British specimen, and that it came from 

 the Marlstone. 



As mentioned above, the specimen regarded as the type, and 

 figured, originally formed part of the Tesson Collection. It has the 

 following measurements: diameter (without test near aperture), 

 204 mm.; thickness (without test on each side), 136 mm.; width 

 of umbilicus (test present on each side), 33 mm. One-third of the 

 last whorl is occupied by the body-chamber. The specimen does 



1 In regard to this specimen Mr. Buckman writes me as follows: "The label is 

 one of my father's ; the writing on it is very similar to his. Many specimens in the 

 Museum were presented by my father, and it is therefore quite likely that he collected 

 this specimen himself." 



