55 



crevice thus formed some one of the many springs abound- 

 ing within a few yards of the spot may have discharged its 

 calcareous waters, and if the crevice was such as to afford 

 no way of escape for any creatures that fell into it, we have 

 all the conditions necessary for the formation of this fossili- 

 ferous stalagmite. 



We must therefore assign to these remains a date not 

 more than one- third or one-fourth of the post-glacial inter- 

 val, that is to say, a few thousand years at the most. The 

 crevice is a record of disaster that befell some of the inhab- 

 itants of the region, among which the tortoises have been 

 the most unfortunate. 



PSARONIUS. 



H. HERZER. 



This fossil plant, also known as PsaroHthus, Helmintho- 

 lithus, Sternstein, Madenstein, Starstone, the stem often 

 several feet in thickness, attaining a height of about six 

 feet, forming a low growth forest, especially so during upper 

 Coal Measures, has been described by Grand 'Eury as a 

 cylindric stem, altogether covered at its base by a texture of 

 roots whereby the leaf scars w+;re obliterated and he thinks 

 that the upper part of these stems can be safely considered 

 as the cylindric parts of some ferns, as Caulopteris or Pro- 

 topteris. The main mass is considered to consist of numer- 

 ous simple adventive or aerial roots, grown through a very 

 thick cortical parenchyma, the bulky mass enclosing a com- 

 paratively very thin cylinder supported by interrupted loose 

 concentric rings or vermicular forms of fibro-vascular 

 bundles, running as vertical folds through its cylinder. 



In the Pennsylvania Coal Flora Lesquereux says : "To 



