450 PALEONTOLOGY OF ILLINOIS. 



and the form of the vascular scars is totally different. The 

 surface is also striated in another manner. Our species repre- 

 sents a new type, till now peculiar to America, and far more 

 different from the true Sigillarios than is the genus Syrigodeiv- 

 dron, Ergt. . Locality: Colchester. 



Sigillaria sculpta, Lsqx. Geol. Rept. Penna., p. 871, tab. 13, 

 fig. 3. Locality: Duquoin, Perry county. 



Sigillaria Menardi, Brgt. Hist, des Veg. Foss., 1, p. 430, tab. 

 158, fig. 5, 6. The figured specimen of our pi. 43 was found 

 by myself at Colchester, and belongs to the State Cabinet, at 

 Springfield. It shows the scars of the leaves and the broad 

 round cicatrix of a branch. This cicatrix makes of our species 

 a true Ulodendron, nearly related, indeed, to Ulodendron punc- 

 tatum, Sternb., while the scars of the leaves show it to be a 

 true Sigillaria. I can not see any difference between this 

 species and Sigillaria Menardi, Brgt. The outline of the scars, 

 as it is seen from the figure, is very variable, passing from 

 rhomboidal, pointed at both ends, to conical-obtuse, then to 

 enlarged-polygonal, and even to acute-hexagonal. The differ- 

 ences are easily accounted for by a difference of direction of 

 the angles, according to an irregular compression of the sides, 

 following the place occupied by the base of the leaves. The 

 branch scar is broadly oval or nearly round, bordered by a 

 small margin, narrowly and irregularly wrinkled, with a small 

 axis, marked by a deep cavity. 



The specimen figured here is of true scientific interest, first, 

 in showing the great variations of the leaf-scars, even on a sur- 

 face of small extent; secondly, by proving that the genus 

 Ulodendron, as it has been established, represents only 

 a peculiar state of some species of Lepidodendron — or rather, 

 that some species of the genus Sigillaria, belonging to the sec- 

 tion of the Leiodermarice (without ribs), are more nearly related 

 to the genus Lepidodendron than to the costate Sigillaria. 



