152 NEW YORK STATE MUSEUM 



its characters indicate a beach sand. The Calciferous, though a> 

 limestone, must have been within reach of relatively swift cur- 

 rents charged with moderately coarse sand. The sand is general 

 throughout the bed that contains it and is not in layers. It was- 

 afforded with some uniformity. In the Trenton times conditions 

 evidently varied. Up through layer 3, sedimentation quietly and 

 uniformly progressed, but at the time layer 4 was deposited there 

 was an influx of sand and water-worn pebbles of large size, which 

 are now mixed with rounded fragments of fossils and limestone. 

 The sand is quite uniformly distributed through the rock, for 

 some thickness. The pebbles and the sand were derived from the- 

 neighboring crystallines, and may have been mixed up with the 

 lime by floating ice. The fact that the pebbles are of gneiss 

 materially modifies the conclusions of Dr Buedemann as set forthi 

 on page 78 of his paper {Amer. geol. 1898) in the discussion 

 on the conglomerates in the Trenton, for he only knew of 

 limestone pebbles at the time. They appear to us to demonstrate 

 neighboring land areas of the archaean. While therefore the 

 paleozoic sea evidently encroached on the ancient crystalline 

 area, and may indeed at one stage have gone entirely over it, yet 

 in the Trenton it did not cover it, and it is reasonable to suppose- 

 that, as the sea encroached in the Potsdam and Ordovician times, 

 it set up estuaries. It is, however, certain that the walls of the 

 Sacandaga valley are not the boundaries of the ancient estuary, if 

 such existed. 



Series 6. The glacial deposits are widespread in the town. On 

 the hills they are morainal, and often contain large boulders. 

 Gneiss, gabbro and anorthosite are the chief rocks present. In 

 the valleys, water-sorted sands and gravels are the rule and near 

 Wells the latter form pronounced terraces. Near specimen 178 r 

 to the southwest of Wells village, glacial striae were observed 

 on the hornblendic gneiss which there outcrops. Their direction 

 is n 40 e magnetic, or n 52 e when referred to the true north. 

 This corresponds with the general experience in eastern Hamil- 

 ton count} 7 . Boulders of Potsdam were noted near by. 



