98 Geological JS/'otkes, 



perhaps a majority of them intersect the strata, nearly at right angles. 

 The dip of the strata is very variable. In many places the strata are 

 nearly, or quite vertical, and in some others they approach the hori- 

 zontal, and vary indefinitely between these limits, and in some local- 

 ities they are bent or contorted so as in a short distance to assume ev- 

 ery possible variety of dip. The general line of bearing of the strata, 

 corresponds with the direction of the chain of mountains, which is 

 about N. N. E. and s. s. w. Augite, serpentine, the primitive lime- 

 stones, magnetic oxide of iron, and various mixtures of these with 

 each other, and with other minerals, constitute almost innumerable 

 beds, of small extent, scattered through the Highlands, in every di- 

 rection, without any regularity in their disposition. Nearly all the 

 varieties of pyroxene are found in our augite rocks. Silicious lime- 

 stone occurs in but one locality, in place, in the Highlands, but is 

 scattered in bowlders and gravel in every direction through them. 



Pyrophyllite, (as it has been recently called in the scientific jour- 

 nals) occurs near West Point in a vein, a foot in width, traversing 

 gray augite. A fragment of it, one eighth of an inch in thickness, 

 exfoliates by heat to such a degree as to become an inch thick. 



A conglomerate rock is now in process of formation, about one 

 mile N. N. w. of West Point, and on the shore of the Hudson, a fine 

 section of it is visible. The cliff rises nearly vertically from the 

 shore from twenty to forty feet, and is composed of fragmentary 

 matter, varying in size, from fine gravel, to bowlders weighing sev- 

 eral hundred pounds. These materials are passing into the state of 

 a solid aggregate, by the continual deposition of calcareous matter 

 between the fragments. The gravel above, as well as the aggregate 

 itself, is composed mostly of pebbles and pieces of various sizes, of 

 slate, lime-stone, hornstone, granite, sienite, &:c. The lime-stone is 

 continually undergoing solution by the infilu'ation of water, and a 

 skeleton of hornstone, or of loose silicious matter, frequently contain- 

 ing the impressions of terebratulae, and some other species of shells 

 remain. The calcareous matter dissolved in the upper part of the 

 bed, is mostly deposited, as is evident on inspection, in the lower 

 portion of it, and in some places, ordinary specimens of dog-tooth 

 spar, (chaux carbonatee Metastatique of Haliy) may be obtained, in- 

 vesting the pebbles. 



Scapolite and sphene are uniformly associated with the augite 

 rocks in this vicinity. Hornblende exists as a constituent part of 

 the sienitic rocks, but it not unfrequently occurs forming distinct 

 beds. The summits of several of the hills in this vicinity, are cap- 



