LYCOPODIALES— LEPIU0DENDKEJ3— OMPHALOPHLOIOS. 227 



specimens, is present and faintly visible in many of the bolsters of tlie frag- 

 ment, Fig. 5, PL LXVI. Although but little wider than the oval boss, it is 

 much longer, extending in this case a little beyond the large boss and 

 including as usual the upper punctiform trace near the truncated upper 

 margin of the bolster. In some respects the large, shallow depressions in 

 this specimen are perhaps analogous to the abnormal or strobiliferoiis scars 

 seen in some of the Sigillarice. 



The difficult task of the interpretation of the details and of the ascription 

 to the structures of their appropriate functions is largely a matter of specu- 

 lation and hypothetical analogy. I shall attempt only to prove some of the 

 homologies between the trunk in hand and others of the Lepidodendroid 

 type, hoping that other paleobotanists more familiar with the Lycopodinece, 

 both living and fossil, will furnish more accurate and valuable correlations. 



The type of cortex before us appears to be one characterized suj^er- 

 ficially by rather strongly protuberant, noncarinate bolsters, exhibiting in 

 outline the general variations characteristic of the Lepidodendi'oid type. 

 These bolsters have large, roundish or ovate triangular bosses, on which are 

 placed the leaf scars and certain other structures. The large bosses were 

 ■ probably highly prominent in the uncompressed stems, and were presum- 

 ably composed, like the other portions of the bolster, largely of soft tissue 

 that has proved very susceptible to distortion and variation under the con- 

 ditions of compression. Their prominence and lack of support well accounts 

 for their partial concealment beneath the folds of the adjacent portions of 

 the bolsters in the flattened im^jressions, as well as for their displacement 

 toward the sides of the bolsters in many cases. The degree of deforma- 

 tion of the bolsters in this trunk exceeds the greatest variations from 

 pressure I have seen in the bolsters of Lepidodenclron Veltheimianum Stb. or 

 L. clypeatum Lx. ' Pressure in a direction probably nearly vertical to the large 

 boss evidently produced the rounded impressions described and figured from 

 the originals by Lesquereux as Leindodendron cyclostigma. From the lower 

 and more prominent part of the large flattened boss two nearly parallel 

 obscurely defined, broad, rounded, perhaps subcoi'tical ridges pass upward 

 across the boss, and apparently a little beyond it, then apparently unite in 

 a horseshoe curve or rounded angle. Within the apex of this loop, and 

 apparently a shoi't distance above the boss, is situated a rarely visible puncti- 

 form trace. I am unable to state whether this long, obscure, vertical loop 



