ARKOSE ON SACHUEST NECK. 285 



and are frequently present on the west and southeast sides of Sachuest 

 Neck. On these sides at least 300 feet of arkose material is exposed. 



On the western side of Sachuest Neck the exposures begin not far from 

 the beach. A coaly shale bed belonging in the arkose series lines the shore 

 at its upper margin, against the hillside, for a long distance. Fern-leaf 

 impressions and species of Annularia occur in this layer just northwest 

 of some old farm buildings. The dip is about vertical or at times very 

 steep eastward at the north end, but southward it is more regularly and 

 decidedly west. Westward, near low-tide levels, the arkoses show a lower 

 western dip, and this low westward dip becomes more marked and more 

 general southward. At very low tide the arkose series is seen to change 

 from its ordinary strike of N. 15° E. to N.-S., and then to N. 20° W. north- 

 ward at one point near the northern end of these western exposures. These 

 features probably indicate a secondary synclinal structure west of the neck. 

 The westward dips continue as far as the point. Near the point the strike 

 is about N. 23° E., dip 45° W. Along the east side of the point there is a 

 well-marked fold whose axis trends N. 8° E. This can be followed north- 

 eastward along the shore, and 250 feet north from its most southern expo- 

 sure the axis of the fold turns quite abruptly eastward, so as to trend 

 N. 50° E. Then it changes again to a more northerly direction, showing 

 synclinal structure on the northwest side, and on a larger scale on the 

 southeast, the trend northward seeming to be N. 16° E. Not far from the 

 most northeastern exposures of the arkose series a small fold is shown, its 

 axis trending N. 8° E., its anticlinal nature being- not at first sight very 

 noticeable, owing to a slight overturn of the fold in part of the exposure. 

 The most eastern arkose exposures show a strike about north-south; the dip 

 is about 20° to -30° W. Along this most eastern exposure the arkose at 

 low water shows on the east of the normal arkose a very granitic-looking 

 rock in which the feldspar can be easily recognized. Farther up the beach, 

 near high-water mark, the arkose shows at its base a mass of unquestioned 

 coarse porphyritic granite, about 3 feet long, with phenocrysts of feldspar, 

 like those at the Cormorant Rock, over a mile southward, and elsewhere. 

 It can not be determined whether this is only an included bowlder or the 

 upper part of the granitic mass which once furnished the material for the 

 arkose. From the well-preserved feldspars in the granitic rock toward 

 the sea, it is evident that if this lower rock be not itself granite the original 



