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PROt 'DINGS OP THK GEOLOGICAL SOCIETY. 



anu flattened at tho top, exactly as somewhat strong fistulous stems 

 would be. It is obviously impossible that casts of medullary cavities 

 could bo preserved in this manner. Neither Sternberc/ice nor casts of 

 the pith of Calamodcndra ever occur under such circumstances. 



8. The stems of Calomites may be seen to have produced leaves 

 and branchlets in such a manner as to prove that they are complete 

 stems preserving their external surface. In my paper on the South 

 Joggins, I figured and described the leaves of (/*. Chtii as seen 

 attached to the erect stems. I have since, in ' Acadian Geology,' 

 figured those of C. Suclcovii, found under similar circumstances; and 

 I have specimens v^ ich appear to me to verify tho figure given by 

 Lindlcy and Hutto, jf the leaves of C. nodosus. I have also ob- 

 tained beautifully preserved specimens of the leaves of C. transi- 

 tionv, a species common to the Devonian and Lower Carboniferous. 

 It haa been supposed that the scars on the nodes of C(damites are 

 merely the marks of bundles of vessels passing from the interior to- 

 wards the surface ; but it is obvious that, in the case of stems actually 

 producing leaves and branchlets, this cannot be the true explana- 

 tion, though after seeing the very instructive slices of Prof. William- 

 son's CaLuno2ntus, kindly shown to me by him, I am prepared to 

 admit that in some specimens, at least, they may represent the 

 " medullary radii," which, as already stated, sometimes appear in 

 addition to the true vascular scars. 



4. The leaves of Ccdamites were not, as is often stated, identical 

 with those oi AsterojihylUtn ; and the genus Calamocladus, in which 

 Schimper has placed many plants of the latter genus, is therefore 

 altogether unnecessary. A careful microscopic examination of the 

 leaves which I have found attached to Calamites convinces me 

 that they have distinct characters, and affords an additional link 

 of connexion with Etivlsetacca). The leaves of AsterojdiyUitcs proper 

 are flat, expanded in the middle, and with a distict midrib. Those 

 of Calamites are strictly linear, thick, and angled, and are be- 

 sides marked with transverse lines or striffi. Similar transv^-se 

 hncs occur on the branchlets of some modern Equiseta, and are 

 produced by hues of minute stomata. WeU-preserved specimens of 

 Lalamite-leaves have precisely the same appearance, so that they 

 may be compared to branchlets of Equiseta deprived of their sheath. 

 J^lattened leaves of Calamites, it is true, sometimes present the ap- 

 pearance of a midrib; but this arises either from the prominence of 

 the upper angle, or tho appearance of an internal axis through tho 

 substance oi the leaf. Unless very badly preserved, they can always 

 be distmginshcd from Asteroi^hyllites or Anmdaria. The connexion 

 3""^ /' by Ettingshausen and others, to obtain between Calamites 

 nr frnt f''?'^. f- ^'' ^"''" ^^^^^^ ^'^^ accidental association, 

 eoileslS'.' ^"^ ^''^'f^''^ leases and stems of Ccdamites from the 



n^r tW li''"^ 1 "^ f^'^r^^^I^^iii^'*' The conjecture of Brong- 

 mart that some, at least, of the Astero^hylUtes may be leaves, not of 



clul^trrS tS^^^^^ H.. appears to consis. of. or to in- 



^'^^-•<U>hintc..l.omT:^^^^^^^^ doubt whether tho proper 



Wala 



