E. Hitchcock on a Bowlder in Amherst, Massachusetts, 397 



pulverised, forming the little soil which supports some of the 

 scattered and scanty patches of vegetation on these islands. 



The minerals embraced in this rock are generally confined to its 

 upper part where it unites and passes into the incumbent amyg- 

 daloid, and many of them are also in common with that rock. 

 They consist chiefly of quartz, crystalline and amorphous, ame- 

 thyst, chalcedony, cacholong, agate, red jasper, felspar, zeolite, 

 calcareous spar in rhombic crystals, sulphate of barytes, a minute 

 crystal resembling black spinelle, sulphuret of iron and green 

 carbonate of copper. 



The only appearance of an organized remain that I anywhere 

 saw, was a fragment of carbonized wood imbedded in this con- 

 glomerate. It was in a vertical position, about two and a half 

 feet in length and four inches in diameter : its color is black, ex- 

 hibiting a fine ligneous structure, and the concentric circles are 

 distinctly visible on its superior end ; it occasionally gives sparks 

 with steel, and effervesces slightly in nitric acid. 



There are a number of active volcanoes in the vicinity of these 

 islands, indications of which are daily seen in the pieces of pum- 

 ice found strewed along the beach. Capt. Weddel saw smoke 

 issuing from the fissures of Bridgeman's island, a few leagues to 

 the northeast. Palmer's land is situated one degree south : what 

 little is known of it, which is only a small portion of its north- 

 ern shore, contains several. Deception island also one of this 

 group, has boiling springs, and a whitish substance like melted 

 feldspar exudes from some of its fissures. * * * * 



Art. XXXV. — Description of a large Bowlder in the Drift of Am- 

 herst, Massachusetts, with parallel strice upon four sides; by 

 Professor Edward Hitchcock. 



In grading one of the streets in Amherst last year, the surface 

 of a large bowlder, or ledge, in front of the residence of Hon, 

 Edward Dickinson, was brought to light, on which numerous 

 rather fine but distinct striae were exhibited, whose direction cor- 

 responds essentially with that taken by the drift agency in this 

 region, viz., south a few degrees east. This fact led me to sus- 

 pect the rock to be the top of a ledge : but on probing the earth 

 around, I found it to be a bowlder. The present summer I pro- 

 posed to my class in Geology, (which is the Junior Class in Col- 

 lege), to dig around the specimen, and try to remove at least the 

 top of it to the vicinity of the Geological Cabinet, about half a 

 mile distant, where it might serve as a fine example of striae to 

 future classes. They promptly engaged in the enterprise, and 

 on digging around the specimen, found it to be of an oblong 



