150 W. Carriithers — Halonia and Lepidodendron. 



only occasionally present. I have no doubt that these represent the 

 stem scars of Lepidodendroid plants which had persistent leaf 

 bases ; and consequently that the species of Bergeria must, like so 

 many other Palaeozoic species, be considered as provisional, and to 

 be set aside as soon as they can be referred to their triie places. The 

 sequel will, I hope, make this obvious. 



The most perfect specimen of Halonia, as regards its external 

 aspect, is that of which a fragment is represented at Fig. 3 of PI. 

 VII. This specimen I obtained in shale at Ebbw Vale, when I was 

 examining the fossils of that district, under the guidance of my 

 friend W. Adams, Esq.. F.G.S., of Cardiff. The outer surfaces of 

 the persistent imbricated bases of the leaves are well shown. On 

 leaving the stem, the leaf took a downward direction, so that at first 

 sight a false impi'ession is obtained of the distal end of the branch. 

 It is properly drawn on the plate, with its proximal end downwards. 

 The cicatrix is very small compared with the exposed portion of 

 the leaf base, and is seen to occupy only the lower angle. That the 

 large tubercles were covered with leaves has been over and over 

 again noticed, and is well shown in this specimen. One of the 

 tubercles is represented at Fig. 4 on the Plate. The upper leaves 

 have been removed, but a nearly complete cirole is seen surrounding 

 the cone, and these have a downward direction as on the main 

 branch. The tubercles when well preserved show a perforation in 

 the apex, through which a large vascular bundle has passed. The 

 arrangement of the leaf bases, and the form of the leaf scars on 

 this specimen agree exactly with Lepidophloios laricinus, and con- 

 sequently confirm the conclusions of Feistmantel. 



I am indebted for the fine specimen represented in PI. VII. Fig. 1, 

 to Sir Ph. de M. Grey Egerton, Bart., of whose extensive collection 

 it formed a part. It is now, by his liberality, placed in the British 

 Museum. The drawing represents a cast taken from the mould, and 

 exhibits what was the external surface of the plant when it was 

 inclosed in the sandstone rock which forms the matrix. This speci- 

 men confirms the observation of Goldenberg, that a Halonia branch 

 may grow out of a Lepidodendron, for here we have the stem of an 

 undoubted Bergeria giving off an equally well-marked Halonia. But 

 the rhomboid scars, as we have already observed, want the true marks 

 of a cicatrix, like that seen in good species of Lepidodendron. They are 

 obviously the scars produced by the separation of the persistent leaf 

 bases at the surface of the stem. I had arrived at this conclusion 

 after a careful examination of a large series of specimens, and of all 

 the published drawings to which I could refer, and I was specially 

 delighted when I found that Geinitz had figured a specimen which 

 confirmed my conclusion, though he had not observed its importance. 

 The accompanying woodcut is a facsimile of a portion of his figure of 

 Halonia punctata, Gein., from plate iii,, fig. 16, of his " Steinkohl. in 

 Sachs." The cortex and leaf bases are converted into coal, as in the 

 specimen represented in Fig. 3, Plate VII. ; but the amorphous cast 

 of the axis is removed. The rocky matrix exhibits the form of 

 the leaves of Lepidophloios, the middle layer shows the rhomboidal 



