202 Miscellanies, 



Calcareous Spar, white, massive, from a vein of the same in one of the 

 rock strata of the island. 

 Galena. 

 Asphaltum. 

 Ferruginous Clay. 



Saline Sandstone, assuming singular configurations, cellular, cavern- 

 ous, and sometimes botryoidal. The forms seem to be derived from the 

 accidental solution of the salt, and wasting away of the sandstone irregu- 

 larly. 



One triangular specimen of saline sandstone is in the form of an irreg- 

 ular tetrahedron, the two axes being unequal. The planes are wasted 

 away, and the solid angles not, so that a continuation of the same pro- 

 cess would leave a cellular substance like the others, but regular. This 

 form is said to be the most common, and although it is not decidedly a 

 crystal, the tendency of its component parts to crystallize and the sym- 

 metry of this specimen, increase the probability that it is. Further spe- 

 cimens and observations are desirable, and the observer should be ac- 

 quainted with the sandstone of Fontainbleau, which suggests itself as 

 analogous in some respects. 



The geological specimens from the same island are compact Quai-tz 

 rock from the summit, JBasaltiform rock, but its identity with basalt is 

 doubtful ; the forms are the chief resemblance in the specimens exhib- 

 ited, which specimens are argillaceous and ferruginous. Their exposure 

 to the weather and contact with other mineral substances, may have 

 caused some change ; and as basalt is sometimes liable to decomposition, 

 it is probable that the specimens are from a formation of true basalt. 

 Striped or Variegated Sandstones. 

 Light Colored Clay Slate. 

 Dark Red Ferruginous Clay. 

 Graywacke. 



Coal has lately been discovered on the island, and fossils are contained 

 in some of the rock strata, so that this little island offers to the geologist 

 in its numerous strata of rocks, with their accompanying minerals and 

 fossils, a more varied field for observation than is usual in so small a 

 space. The committee cannot give the desired geological description for 

 the want of other facts, but hopes to obtain them. 



The fossils consist of small bivalves in the clay slate. 

 Trigonia in graywacke, and casts of Trigonia in the red clay. 

 Ammonites and casts of ammonites, and some small Isocardia. 

 Dr. Brinckerhoff has also collected a variety of the rolled pebbles of 

 the beach. They are principally porphyries of different colors, the feld- 

 spar crystals being smaller and generally white ; siliceous pebbles and 

 common jaspers. 



