COAL ROCKS OF EASTERN VIRGINIA. 305 



Suckowii, is the same as that I am now describing, and is the 

 true Calamites arenaceiis. 



It may, perhaps, be conjectured, without doubting the great 

 sldll of this illustrious naturalist in vegetable Palasontology, that 

 the specimens from Wilkesbarre and Richmond, being presumed 

 by him to have come from the same geological forrtiation, and 

 the very imperfect condition of the Virginia specimen disguising 

 its peculiarities, he failed in bestowing such attention on the 

 subject as would have assured him that the two were of ditferent 

 species. 



According to Brongniart, the C. arenaceus occurs associated 

 with Eqidsetum columnar e, near Studtgard. 



Calamites planicostatus. 



The fossil here referred to is usually met w^ith in the slaty beds 

 containing the Equisehon colinnnare, and is, in some localities, 

 quite as abundant as that plant. The best characterized specimen 

 in my collection has the appearance of a flattened stem, exhibit- 

 ing several distinct articulations, all entirely devoid of tubercles. 

 Throughout its whole length, this impression is marked by shal- 

 low parallel grooves, slightly deepening towards the joints, and 

 distant one from another from the fifteenth to the twentieth of an 

 inch. These grooves are generally prolonged across the joints, 

 so as to be continuous throughout the neighboring divisions of 

 the stem, suffering only a slight flexure and lateral displacement 

 as they cross the articulations, and returning again to the origi- 

 nal line. The ribs or ridges between the gi'ooves are smooth and 

 flat, excepting near the joints, where they are slightly but irreg- 

 ularly convex. At many of these joints, are seen small circular 

 scars, like the points of insertion of leaves, arranged at intervals 

 of about half an inch. One or two extremely fine strias may 

 generally be traced along the middle of each rib. 



From the general flatness of the impression, and the gi-eat 

 shallowness of the furrows, it might at first be readily taken for a 

 large striated leaf ; but, upon removing the coaly film which con- 

 ceals the articulation, the jointed and stem-like nature of the 

 fossil is indistinctly shown. The great thickness of the coaly 



