234 



SCIENCE. 



"N. S. Vol. XVI No. 3ii7. 



ous (Millstone Grit), precipitated the present 

 controversy."^" Also Dr. Ells agrees with Mr. 

 Fletcher in placing the Horton, which Daw- 

 son . referred to the Lower Carboniferous and 

 correctly correlated with our Pocono, in the 

 Devonian, the ' Carboniferous limestone ' be- 

 ing made the lowest formation of the Carbon- 

 iferous.+ A considerable portion of Dr. Ells's 

 article and the whole of the communication by 

 Dr. Matthew, which inunediately follows it in 

 the same magazine,:}: are devoted to proof that 

 Dawson's reference of the St. John plants to 

 the Middle Devonian was not due to the 

 iniluence of his statigraphieal colleagues. 

 This point, on which I seem to have been 

 mistaken, is a matter of history of opinion, 

 and, though interesting as such, does not af- 

 fect the geological facts of the region. 



The latest contribution to the discussion, 

 ' A Backward Step in Paleobotany,' by Dr. 

 Matthew,§ demands respectful attention both 

 for its matter and its dignified place of pub- 

 lication. In part it attempts to meet a call for 

 conclusive stratigraphieal proof that the St. 

 John plant beds are Middle Devonian. The 

 first half of the paper contains a statement of 

 the stratigraphieal arguments in a form more 

 extended than in the American Geologist for 

 June, 1901. Here again the strongest argu- 

 ment seems to be the metamorphism seen in 

 the Little River group and other beds suppos- 

 ed by Dr. Matthew to be older than Carbon- 

 iferous. The first of the profile sections in- 

 cluded to show the stratigraphy of the plant 

 beds is conclusive as to Middle Devonian, if 



*H. Fletcher, Trons. N. 8. Inst. Set., Vol. X., 

 pp. 236-237. 



t The suggestion made by the writer (Can. Bee. 

 8ci., "V"ol. VIII., p. 279 ) that this limestone ' may 

 be much younger than is generally supposed,' by 

 which it was meant that, if the Riversdale plants 

 were actually beneath the limestone, the latter 

 must at least occupy a high place in the Lower 

 Carboniferous, is interpreted by Dr. Ells as neces- 

 sitating the reference of the ' Carboniferons rocks 

 proper ' to the place now assigned to the ' Permo- 

 carboniferous, or possibly the horizon of the Cre- 

 taceous.' This seems a needless alarm. 



t Can. Ree. Sci., Vol. VIII., No. 6, pp. 344-345. 



§ Trans. Boy. Sac. Can., 1901, sec. IV., pp. 113- 

 122. Dated 1901, but printed in 1902. 



it is correct both as to stratigraphy and as to 

 correlation; but in view of the small portion of 

 the diagram occupied by rocks above sea level, 

 the incompleteness of the exj)osures, and the 

 paleontological evidence I find myself unwid- 

 ing to admit so simple a structure. The 

 second of the two sections presents what seems 

 an isoclinal structure involving a fault which 

 is not shown. Any one of several interpreta- 

 tions may be put upon it. Dr. Matthew per- 

 haps understands the true structure; but the: 

 diagram is too equivocal to demonstrate it. 



The remaining half of Dr. Matthew's paper 

 is devoted to proof by paleobotany itself. 

 Here again, as in his former article, his chief 

 argument that the Megalopteris plant beds of 

 the Mauch Chunk in the Appalachian region 

 carried the St. John flora across fro.n the 

 Middle Devonian to the Pottsville, falls flat 

 when we recall that the Megalopteris beds sup- 

 posed to constitute the bridge are now recog- 

 nized by the stratigraphers as not in the 

 Mauch Chunk at all, but as lying within the 

 Pottsville. The discussion of other paleo- 

 botanieal aspects of the St. John plant beds, 

 and especially the doubtful identifications of 

 the older types reported in the latter, requires 

 greater space than is here available; but be- 

 fore passing on it inay be noted that probably 

 over 60 per cent, of the valid plant species 

 found at St. John are also in hand from the 

 Pottsville in the Appalachian trough, while it 

 is very doubtful if three species recognized 

 elsewhere as characteristic Devonian plants 

 are present. 



The paleobotanists do not contend that there 

 are no beds of Middle Devonian age in south- 

 ern New Brunswick, or that all the rocks of 

 jSTova Scotia that have been correlated with or 

 mapped as representing the plant-bearing for- 

 mation at Riversdale are Carboniferous. But, 

 after reading the statements and inspecting 

 the profiles lately iDublished, it still seeTis 

 proper to inqiiire whether, in the closed fold- 

 ing and faulting inevitably indicated though 

 not explained in the section from the vicinity 

 of St. John, some segments of Carboniferous 

 terranes have not been thro^m in a false posi- 

 tion as well as altered ; and whether in tracing 

 the Devonian formations through the largely 



