448 PALEONTOLOGY OF ILLINOIS. 



sidered as varieties, but which most probably are species. 

 Mentioning a few of them, we have : 



var. imdulata, Gopp. With the scars separated by undulate 

 ribs. 



var. reticulata, Gopp. With a reticulated surface. 



var. stellata, Gopp. With the scars surrounded by regular 

 wrinkles, resembling the rays of a star. 



The species is generally and abundantly found in the whole 

 thickness of our Coal Measures. Beautiful specimens of the 

 three varieties enumerated above, found in Pope county, under 

 the upper Archimedes limestone, are preserved in the State 

 Cabinet, together with Stigmaria anabatlira, Corda, Stigmaria 

 minor, Gopp., and Stigmaria umbonata, Lsqx., which can not 

 be separated from this Stigmaria ficoides, unless the other 

 varieties are admitted as true species. 



Stigmaria Evenii, Lsqx. PI. 39, fig. 9. This speces is not 

 comparable to any other form of this genus. It is remarkable, 

 indeed, for the great irregularity of position of the scars, their 

 generally small and at the same time very variable size, some- 

 times as small as a point. They are then approached by two 

 together, while the largest are isolated. Generally they are 

 separated by short undulate ribs, somewhat like those of Stig- 

 maria undulata, Gopp., but less regular and shorter. The 

 central point is obsolete, and sometimes entirely undiscernable. 

 Found at Mazon creek, by Mr. Jos. Even. Coal No. 3. 



Genus Sigillaria, Brgt. Stem large, tree-like or erect, 

 marked on its surface with parallel ribs or reticulated in dif- 

 ferent directions, even nearly smooth, impressed with the cica- 

 trices of deciduous leaves, placed around the stems in spiral 

 or quincuncial order; cicatrices disciform, oblong, or round, 

 with mostly angular sides, the upper part emarginate, marked 

 in the middle by scars of vessels, horizontally placed in three, 

 sometimes two, rarely simple. 



