168 Hall on the 



This species presents much variety of appearance dependant 

 upon the condition of preservation. In specimens most nearly 

 entire, the double midrib often extends beyond the apex nearly as 

 far as the length of the frond ; the margins present a series of 

 oval or sub-hexagonal reticulations, every second one (and some- 

 times each one,) of which is armed by a minute mucronate spinule. 

 When these outer cells or reticulations are broken away, the trans- 

 verse walls between them often remain, and the specimens then 

 present an undulating margin, with a short mucronate extension, 

 which is the original wall between the marginal reticulations, 

 and which is continuous with the striae or fibres which traverse 

 the frond from the midrib to the margins. On each side of the 

 basal extremity the long setiform fibres extend obliquely forward 

 to the distance of half an inch, and between these are two short 

 terminal ones, like the processes on the sides of the frond. 



In many specimens the whole exterior reticulate portion is re- 

 moved, leaving the frond with straight or nearly straight parallel 

 sides, the long extended midrib above, and the two setiform pro- 

 cesses from the lower extremity ; while in some specimens these 

 parts are also removed. The serratures cannot well be deter- 

 mined in any of the numerous individuals examined, but they 

 doubtless correspond to the vein-like markings of the centre, and 

 the reticulate marginal extension. 



Some specimens indicate that the central portion may be finely 

 reticulate, which character, with that of the exterior, would be re- 

 garded as sufficient to warrant us in referring it to the genus 

 Retiolites. 



Locality and Formation. — Point L6vy ; Hudson River Group. 



Collectors. — J. Richardson, Sir W. E. Logan, James Hall. 



Phyllogbaptus. 



Among the various forms in this Canadian collection of Grap- 

 tolitideaz there are several which approach in general form to G. 

 ovatus of Barrande, and G. folium of Hisinger. They present 

 however some differences of character, varying from broad-oval 

 with the extremities nearly equal, to elongate oval or ovate, the 

 apex usually the narrower, but in a few instances the base is nar- 

 rower than the apex. These forms are sometimes extremely nu- 

 merous in the shales, and present on a cursory examination a 

 general similarity to the leaves of large species of Neuropteris in 

 the shales of the coal measures. 



