

. Notice of a Scientific Expedition. 349 



Two Islands, are situated four miles N. E. of the village of Pars- 

 boro. They are composed of amygdaloid and greenstone, and be- 

 neath, is the red sandstone which just appears at low water. At one 

 of the Islands, there is a splendid arch way which has been formed 

 by the action of the tide on the porous amygdaloid. The minerals 

 which may be sought for, are needlestone in snow white and brown- 

 ish implanted crystals of the lustre of satin, analcime and heulan- 

 dite colored greenish gray by some foreign substance. The heu- 

 landite is modified by replacement of the acute lateral edges, and 

 the obtuse solid angles. Generally both modifications are combi- 

 ned in the same crystal, the replacement of the acute lateral edge, 

 is often so deep that the crystal becomes a six sided prism. 



Swan's Creek in the immediate neighborhood of Two Islands, fur- 

 nishes fine needlestone in white crystals, and also a variety which 

 is hair brown in extremely thin individuals. It is sometimes called 

 hairstone. The base of those compound masses is generally anal- 

 cime, and needlestone stands out from all the spaces between the 

 crystals like small mats of bristles. - 



Chabasie. — Three circumstances combined render it necessary to 

 speak particularly of the mineral ; 1st, its abundance; 2d, the occa- 

 sional size of the crystals ; and 3d, the modifications which they pre- 

 sent. Chabasie seems to take the place of stilbite, and the other 

 zeolites in this neighborhood. Although the crystals are generally 

 small, yet occasionally they may be found in the debris from one half 

 to an inch in diameter. • 



The following are some of the modifications of the primary form, 

 which maybe obtained here. 1st, the primary with two adjacent 

 solid angles replaced by single tangent planes. 2d, the primary 

 having its upper edges and lateral angles replaced by tangent planes. 

 3d, the primary with its superior edges replaced by two planes pro- 

 ducing a dodecahedron with isosceles triangular planes. The latter 

 solid is occasionally found complete. The manner in which crys- 

 tals of chabasie are grouped or clustered, adds much to the difficul- 

 ty of studying the modifications of the primary form. 



Siliceous Sinter occurs in balls or ovoid masses, generally white, 

 but frequently purple. The interior is often lined by chabasie and 

 small dodecahedral crystals of carbonate of lime. -, 



About two miles from Swan's Creek there is a locality of tolera- 

 ble good pyroxene in the usual form of six sided prisms ; on the 

 surface of these crystals and in the interstices, is a small reddish 



