GEOLOGY. 307 



translucency in thin layers ; the powder is light ash-grey, becoming 

 reddish by ignition ; when exposed to heat in a tube, ammoniacal 

 water is evolved, with a strong odor of animal matter, like that of 

 burning horn. A fragment of one of the cylindrical bodies was freed 

 as much as possible from the sandstone which adhered to the interior, 

 pulverized, dried and submitted to analysis. It dissolved in hydro- 

 chloric acid with slight effervescence, from the presence of carbonate 

 of lime, derived in part from the adherent rock which is calcareous, 

 and left a considerable residue of quartzose sand. The analysis gave 

 in 100 parts, 87.53 phosphate of lime, 2.15 volatile matter, with a 

 little carbonate of lime, magnesia, and oxide of iron. 



Many of the cylindrical bodies found in this locality have an axis of 

 foreign matter, and others have a singular resemblance to different 

 bones ; others again from their form and homogenous texture resem- 

 ble coprolites. They are generally very compact, with a fine grained 

 conchoidal fracture ; their color is dark blackish-brown, or ^bluish- 

 black, and that of the powder ash-grey, becoming reddish-brown by 

 heat. Heated in a tube, a strong odor of burning horn is evolved. 

 Sections of these substances have been made, and submitted to micro- 

 scopic examination. The hollow cylindrical mass appears homogen- 

 eous and finely granular in its texture, while a fragment from the 

 conglomerate bed, consisted of a finely granular matrix, in which are 

 imbedded angular grains, apparently of quartz. Throughout the 

 mass of the latter specimen are found imbedded small transparent cyl- 

 inders, which are almost colorless, and appear to be silicious. Some 

 are nearly uniform in diameter, with hemispherical extremities ; oth- 

 ers are thicker in the middle, and taper to the ends, which are either 

 rounded or conical ; they are generally more or less curved, and are 

 from 1-100 to 2-100 of an inch in length. Some of them exhibit 

 traces of a longitudinal cylindrical axis, which appears to be a canal 

 filled up with some granular matter. According to Dr. Bacon, of 

 Boston, they resemble the silicious spiculre which occur in some of 

 the sponges and other zoophytes, but he regards his examination as 

 yet incomplete. The results are conclusive as to the absence of any 

 bony structure in the specimens. At the same time the external form, 

 connected with their peculiar composition, which is identical with that 

 of fossil bones, prompts the inquiry whether any metamorphic agen- 

 cies could not have so far acted upon the animal remains as to induce 

 an incipient crystallization of the phosphate of lime, thus obliterating 

 the organic structure. Such a change is well known to take place in 

 fossils consisting of carbonate of lime, as the stems of crinoids, which 

 are often highly crystalline in their texture. 



Further examinations have also enabled Mr. Hunt to detect these 

 phosphatic nodules and cylinders in various other localities, in the 

 ancient palaeozoic sandstones. Although the presence of these pecu- 

 liar animalized phosphatic masses, in different parts of the Lower 

 Silurian rocks, points to the existence of vertebrate animals at that 

 geological epoch, as the only hypothesis which in the present state of 

 our knowledge, can account for the origin of such substances, it will 

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