158 



alcyohic structure, the action of the muscular fibres would have 

 casioned such changes of form as are here noticed, and as would, 

 by enlarging or lessening their central cavity, necessarily affect their 

 buoyancy. 



These fossils are found in prodigious quantities, in mountainous masses, 

 in different parts of Hungary, Transylvania, Switzerland, France, and 

 Italy. But perhaps these fossils exist no where in more abundance than 

 in Tuscany; where, according to Targioni Tozzetti, they are to be 

 found, particularly in the mountain of Parlascio, forming strata three 

 yards in thickness, and mixed with all the several minute shells which 

 have been figured by Bianchi, in his work, De Conckis minus notis, &c. 

 Voyage en Toscane, fc. Tome n. p. 148. 



To my kind correspondent, Mr. J. Holloway, of Portsmouth, I am 

 very much obliged for being enabled to ascertain the existence of these 

 fossils in this island. This gentleman furnished me with several of 

 N. tavigata, from Stublington Cliff,. between Stokes' Bay and Southamp- 

 ton Water. 



Although from the minuteness, as well as the imperfect state of the 

 few specimens which I possess, I may be unable fully to dev elope the 

 structure and determine the nature of the fossil now placed before you, 

 Plate X. Fig. 28, it is yet hoped, that sufficient will be shown to ren- 

 der it interesting. An examination, with a powerful lens, was neces- 

 sary, to discover most of those peculiarities, in the structure of this fossil, 

 which will be noticed in its description. 



LXXXIII. Fasciolites. A subcylindrical, shelly, or bony body, about 

 half an inch in length, rather tapering at the ends, and formed by the spiral 

 arrangement of perpendicular, concamerated tubes, the tapering end of 

 each of which is obliquely and transversely folded on that of the pre- 

 ceding one. 



The appearance which this fossil offers to the naked eye is shown. 



