Geology and Mineralogy of Salisbury. 255 
In the south part of the town the limestone presents a 
curious appearance. In an abrupt hill of mica-slate seve- 
ral hundred feet in height, it formsa regularsegment of a cir- 
cle supporting the slate. The ledge where this is seen to 
the best advantage ts perpendicular, about seventy or eigh- 
ty feet high. The limestone rises fifty feet, and gracefully 
bending forms the arch. The rocks are united so as to 
present the appearance of having come in contact when 
in a state of partial solution. The limestone is magnesian, 
and appears to form the nucleus of the hill. 
The dolomite of this region is to a great extent flexible, 
and much resembles the magnesian limestone of Sunder- 
land, Eng. Like that it dissolves in acids as readily as 
pure carbonate of lime. Its flexibility however does not 
appear to diminish by loss of moisture. Pieces of a small 
size which have lain on the surface of the ground for years, 
appear as flexible as when newly dug. In this respect al- 
so,it resembles the Sunderland limestone, whose flexibility 
remains after the water has entirely escaped. 
The surface of the limestone is often colored by the de- 
composition of sulphuret of iron, besides which it contains 
tremolite, tourmaline, mica, talc, &c. | 
Alluvial. 
The alluvial deposit of this town is of considerable ex- 
tent. ‘Taking Eaton’s division of primary and secondary, 
the former embraces the iron ore beds, and many valleys 
remote from the principal streams; while the latter forms 
the banks of the *Hooestennuc and its tributaries. Indian 
skeletons are often washed from the bank in nearly a 
perfect state of preservation. Trees also are frequently 
Jaid bare, which have probably been hid for centuries.— 
These, when exposed to the atmosphere, soon decay. 
Simple Minerals. 
Carbonate of Lime, abundant, sometimes phosphores- 
cent, intersected with Calcareous Spar, both crystallized 
*See Pres. Dwight’s Travels. 
