PLANT-REMAINS OF DOUBTFUL AFFINITY, ETC. 369 



the needful proofs in any direction until we can examine specimens in 

 which the structure is preserved. 



The Spirangiae do not represent a perfectly isolated type ; that 

 there may have been a whole group of similar forms in existence, may be 

 concluded from the recent discovery of the genus Fayolia 1 by Renault 

 and Zeiller in the coal-mines of Commentry. Figures and a full description 

 of this form may be expected in the great Elora of Commentry, upon 

 which these authors are engaged. The resemblance between Fayolia and 

 Spirangium is obvious, though in the former there are only two much more 

 strongly twisted screw-lines, which appear to answer to the margins of two 

 ribbon-like valves. On each of these is an appendage (' collerette ') peculiarly 

 striated and entire or toothed, which is prolonged beneath the beak of 

 the body into a free erect pointed and winged tooth. The plates them- 

 selves bear a row of small circular scars, which approach the lower margin 

 and represent the points of attachment of subulate spines which are 

 occasionally preserved. 



Some identical remains have been recently and almost simultaneously 

 described by Weiss 2 and Newberry 3 , which appear to be allied to Fayolia 

 but are unfortunately in a much worse state of preservation. Gyrocalamus 

 palatinus, Weiss, was discovered in the Rothliegende (Lebach beds) near 

 Cusel in the Rhenish Palatinate ; Spiraxis major and S. Randallii of 

 Newberry come from the Chemung beds of the Upper Devonian formation, 

 the former having been found in the State of New York, the latter in 

 Pennsylvania. If these forms, as Weiss 4 assumes without any hesitation, 

 are really to be classed with Fayolia, it would not say much for the re- 

 lationship of that genus to Characeae ; for both Gyrocalamus and Spiraxis, 

 owing to their greater length and more cylindrical form, have much 

 less the appearance of fructifications. The unprejudiced observer would 

 take Weiss' fossil, which is broken off at both ends, simply for a fragment 

 of the cylindrical cast of a stem. The surface unfortunately is very 

 imperfectly preserved, the American specimens showing only the strongly 

 projecting broad obtuse ribs running in very flat spirals ; in the German 

 specimen we see that each of the apparently simple ribs consists of two 

 parts, an inferior sharp keel, the proper rib, and a flatly convex strip 

 lying upon it, which belongs to the twisted band and bears a row of in- 

 distinct roundish scars exactly at the spot where the scars of the spines 

 appear in the better preserved remains from Commentry. 



We may now turn in conclusion to the genus Williamsonia, the last 

 group of fossil remains which we shall have to consider. The species of 

 Williamsonia are very peculiar remains of fructifications, and their precise 

 structure is still very imperfectly known to us. That they are associated 



Zeiller (12). 2 Weiss (5), p. 238, t. 4. * Newberry (1). 4 Weiss (5), p. 288. 



Bb 



