20 NEW YORK STATE MUSEUM 



ing valleys. The Branch cut away the delta face and gave particu- 

 larly good exposures of which the writer, fortunately in the field 

 at the time, obtained the photograph shown in plate 8. The cross- 

 bedding and the upper horizontal beds both come out very clearly. 



This terrace has been the scene of one of the ill advised placer- 

 mining excitements which spread periodically through the moun- 

 tains. It was prospected by pits in 1895 for supposed gold and 

 platinum. 



At the mouth of Roaring brook, just north of New Russia, there 

 is another fine delta terrace placed on the map at a little below the 

 600 foot contour, but the difference is not great and its upper level 

 was doubtless due to the same hight of water as the one at 

 Elizabethtown. 



Along the Schroon river and just west of Holiday pond there is 

 an extensive gravel terrace with pebbles up to 2 inches, and with its 

 top at the 980 foot contour. There must have been ponding of 

 waters at this locality, higher than the Elizabethtown level of 600 

 feet and the pebbles are so coarse as rather to argae delta condi- 

 tions, than a lake bottom. The ponding may have been conditioned by 

 a temporary ice barrier. Still farther south a terrace is again pro- 

 nounced between 940 and 960, where the highway crosses and 

 leaves the sheet. The difference in altitude between this one and 

 the one to the north is not great and they may have been the 

 result of the one hight of water. 



Stream terraces. At several places stream terraces are beauti- 

 fully shown. In the southeasterly oxbow of the Boquet river, in 

 the northeast corner of the Elizabethtown sheet, extending into the 

 Ausable sheet to the north are four terraces, respectively at 8, 18. 

 22 and 40 feet above the creek, which is here at the 400-foot 

 contour. An additional indistinct one is half way between the 8 

 and 18 foot ones. Again along the Schroon as it leaves the south- 

 ern edge of the sheet, there are four terraces, respectively at 894, 

 900, 920 and 940 feet. Both of thse are due to the meanders and 

 downward cutting. 



Sand dunes. In the extreme northeastern corner of the Eliza- 

 bethtown quadrangle and in the point of land between the Boquet 

 and the Black rivers, there is a very sandy area marked by small 

 drifting dunes and by interesting wind-blown phenomena of this 

 character. Ripple marks appear over a portion of the sandy ex- 

 panse. The whole aspect irresistibly suggests the seashore. 



