492 H. HICKS ON THE REMAINS OF PLANTS FROM THE 



cells are more or less circular, and are separated by greater or less 

 interspaces in different parts of the section. 



Compared with the Nematophycus Logani as figured by Mr. Car- 

 ruthers, the minute structure of these carbonaceous fragments will 

 be found to agree precisely, with the one exception that the finer 

 tubes or cells filling the interspaces between the larger ones, which 

 Mr. Carruthers figures and describes in Nematophycus, are not so 

 distinct in Dr. Hicks's specimens. The double spiral fibres figured 

 by Dr. Dawson when he first described his Prototaocites { = Nema- 

 tophycus, Carr.), are rather to be referred to the interlacing cells 

 (network in Pen-y-Glog specimens) than to the fine spiral fibres 

 seen in the latter (fig. 4). 



The rounded seed-like bodies found with the carbonaceous frag- 

 ments are hollow and thick -walled. In microscopical sections the 

 wall is found to be composed of radiating fibres (cells ?) arranged 

 nearly parallel to each other and slightly wavy (fig. 8). These cells 

 are irregularly filled with spore-like bodies. The seed-like bodies 

 resemble the Pachytheca from the Upper Ludlow beds both in 

 their outward form and in the radiated structure of their walls. 



The question naturally arises, Are the carbonaceous fragments 

 so well known to occur in the Ludlow bed (Downton sandstone) of 

 the same nature and structure as the Denbigshire-grit specimens ? 

 Mr. Newton has not been able to obtain transparent sections of the 

 Ludlow woody specimens ; but, from what little we have been able 

 to make out, these Ludlow fragments likewise show tubular struc- 

 ture, but not quite of the same character as those from Pen-y-Glog. 



On first seeing Dr. Hicks's specimens I pronounced the remains 

 to be those of some marine Alga ; but T was not then acquainted 

 either with Mr. Carruthers's paper on Nematophycus or Dr. Dawson's 

 description of Prototaocites, neither being then known as British 

 plants ; and no opportunity had occurred to me for examination. 

 The sections made by Mr. Newton reveal in the most perfect and 

 satisfactory manner the innumerable vermicular cellular filaments 

 which constitute nearly the entire structure of what must have been 

 the stem, and also the dense spongy nature produced by the smaller 

 tubes, which seem to ramify irregularly. The larger tubes are not 

 strictly parallel to each other, although they run in the same general 

 direction ; they appear to be continuous, and their ends bluntly 

 rounded. 



The description of the structure of Nematophycus, and the discussion 

 .of its affinities with certain orders in the Chlorospenneae, are so ably 

 and completely done by Mr. Carruthers, that little is left for further 

 description, especially as there is no doubt whatever that the plant- 

 remains in the Denbighshire Grit from Pen-y-Glog are unques- 

 tionably Nematophycus of Carruthers, and the Prototaocites and 

 Nematoocylon of Dr. Dawson, referred by Dr. Dawson to the Coniferae 

 through the Taxinese or Tews. 



The fragments, small as they are, show unmistakably that we 

 have at this low horizon the Gaspe plant (Prototaocites) which occurs 

 in the Devonian rocks of America. This is an important fact, as 



