United States Exploring Expedition. 21 



amples of this genus, may represent different species of Sigiilaria in a de- 

 micorticated state. 



Decorticated specimens are by far the most abundant. Lindley and 

 Button's figure of Sigiilaria reniformis (PI. 57), affords a good illustra- 

 tion of the kind displayed on that division of the diagram 4, marked B ; 

 while Brongniart's representation of Sig. pyri/ormis (PI. 153, fig. 3), 

 shews the appearance on the division marked A of diagram 3 ; the for- 

 mer exhibits an impression of the inner surface of the cuticle, and the 

 latter shews an impression of the outer or original surface of this part.* 

 I have a single observation to make respecting specimens of the first di- 

 vision, which is, that they expose the vascular scars situated on convex 

 ribs, with the exception of the previously noticed specimen from North 

 Biddick. It is necessary to bear this in mind, as it is highly probable 

 that hand specimens may be found displaying the same character, and 

 as such will be otherwise inexplicable. 



What has now been stated will, I think, make clear the mode in which 

 one specimen of Sigiilaria may afford six different appearances ; should 

 this be admitted, it necessarily follows, that, of the sixty or more species 

 which have been described of this genus, a great many are purely facti- 

 tious : other considerations to be adduced hereafter will tend still further 

 to reduce this number. 



(To be continued.) 



United States Exploring Expedition. 



England and France have long been honourable rivals on 

 the ocean, as well in exploring as in warlike expeditions. The 

 voyages of Cook, Vancouver, Flinders, Parry, Beechey, King, 

 Fitzroy, and Ross, are conspicuous in the annals of English 

 navigation ; while France is no less honoured by her explora- 

 tions under Bougainville, La Perouse, Labillardiere, Duperrey, 

 Freycinet, and D'Urville. Both countries have looked beyond 

 the mere discovery of new lands, new commercial resources, 

 and territorial aggrandizement. Their efforts have been 

 directed towards an increase of knowledge in every branch of 

 science ; and there are few regions, from the equator to the 

 poles, which have not been tracked by their vessels. What- 



are precisely the same as is seen on the origins of the branches of this fossil i 

 that is, when the characters of the stem become blended with those of the root. 



* The so-called Sigiilaria monastachya (PI. 72) of Lindley and Hutton, which 

 I perceive is erroneously considered by Presl a species of Ulodendron (Sternberg, 

 parts 7 and 8, p. 186) is, I am convinced, a decorticated isolated rib of Sig. reni- 

 formis. The specimen figured in the Fossil Flora is in th« Newcastle Museum. 



