CALCIFEROHS SANDSTONE. 



CALCIFEROUS SANDSTONE. 



Wo find in this rock, in niiincrous localities, a great nnmlier of what appear to he the 

 remains of sea plants. Many of these consist apparent!}' of fragments of large succulent 

 stems, even giving some evidence of having been hollow, like the stems of some of the 

 marine plants of the present day. It is impossible in these, as in nearly all the remains of 

 marine plants of the paheozoic rocks, to detect any structure which can be reliable in 

 making distinctions. In the case before us, we are led to refer these vestiges to marine 

 vegetation, not from their appearance a'one, but fiorn the fact that wtrfind, in cavities 

 of the same roclc, small quantities of anthracite. Now although the present condition of 

 this carbonaceous matter is that of antliracite, we nevertheless believe it to have been a 

 fluid or semifluid bitumen, from the fact that where occurring free in a cavity of the rock, 

 it has indurated in a globular or semi-globular form, indicating a degree of fluidity in its 

 original condition. The very natural suggestion is, that the bituminous matter derived from 

 this vegetation has parted with its volatile parts, and become a solid mass of non-bituminous 

 coal. Whatever weight such an argument may liave, we cannot resist tlie inclination to 

 associate this production with the obscure remains wliicli we find in the same strata. 



From the nature of the rock, and from the condition of many of its fossils, w'e cannot 

 doubt but many more forms, both of plants and animals, were imbedded in it, than we 

 find at the present time. The very obscure impressions and cavities which so frequently 

 occur, in some of which it is not difficult to detect the marks of organic structure, lead us 

 to believe that the sea from which this deposit was thrown down contained a numerous 

 fauna. That their remains are so obscure at the ])resent time, has doubtles arisen from two 

 causes : first, that during the deposition of the mass, there was a considerable intermixture 

 of silica, which to some extent existed in a soluble condition, and, as we infer, absorbed 

 the exuvia; and obscured the characters of these remains ; and again, the proximity of this 

 rock, in its best defined localities, to those of hypogene origin, and the nmiierous faults 

 and uplifts it presents, lead us to believe that it has undergone subsequent changes, which 

 also may have had some effect in obliterating the organic forms. 



In nearly all instances, we find the shells removed, and siliceous casts of the interior 

 only remaining. In a few instances, the siicll is replaced by siliceous matter. Many of these 

 casts are imbedded in a mass of chert or hornstone, tlie material of which has doubtless 

 been aggregated around them after their death, forming nodules or accretions as in the 

 higher.limestones and in chalk. 



During the progress of this formation, and towards its close, a considerable number of 

 forms of animal life appear to have been called into existence. We have passed from that 



