L76 J!. D. SALISBURY — EXTRA-MORAINIC DRIFT. 



the striae are of such a character as to make their glacial origin evident. 

 Even among the pebbles of the stratified portions of the Oxford Furnace 

 deposits, striated pebbles may occasionally be found, indicating that the 



materials have suffered but a limited transport by water. Furthermore. 

 the relations of the stratified and unstratified materials are such as to 

 show contemporaneity of origin. 



In another sense the morainic material and the material of morainic 

 derivation just north of Oxford Furnace are essentially unlike the Oxford 

 Furnace deposits. The one bears every evidence of youth, and the other 

 as strikingly bears evidence of age. In the one ease the days are unox- 

 idized and unleaehed. and the stony material retains the hard fresh sur- 

 faces which characterize freshly glaciated bowlders. Even the sands, 

 readily percolated by water, are calcareous to within three or four feet of 

 the surface. In the other case, the clays are oxidized to great depths, 

 the calcareous material which they presumably contained has been 

 leached out. and a large proportion of the decomposable rock materials 

 which the clay contains have so far yielded to the effects of weathering 

 and solution as to have lost their integrity altogether. So striking are 

 these differences in the two classes of deposits, good exposures of which 

 may be seen within two miles of each other, that it cannot escape notice 

 even in a cursory examination. If 1 represent the age of the material 

 of the moraine, the age of the other can hardly he represented by one 

 figure. 



The higher lands southwest and west of Oxford Furnace are likewise 

 found to be interruptedly covered by a similar drift mantle. It is gener- 

 ally absent from the steep slopes, is frequently present on the gentler ones, 

 and is nearly uniformly present on the level summits. Rising from 550 

 feet near Oxford Furnace to 600, 7<»» and 800 feet, the same till-like ma- 

 terial occurs. Near Little York, about 860 feet above tide, the same 

 bowldery clay is exposed to a depth often feet or more. The stony ma- 

 terial is predominantly small, and the larger portion of the stone is of 

 quartzite or hard sandstone. The quartzites and hard sand-tone- do 

 not commonly show glacial markings, though their surfaces are gen- 

 erally unweathered and sometimes show planation. The fragments of 

 crystalline rocks (crystalline schist series) are almost uniformly so far 

 disintegrated that they would not show surface markings even if once 

 .present. 



Among the stony ingredients at this place there .ire many hits of soft 

 shale. With these the case is very different. These hits of shale, soft as 

 they are, have withstood the disintegrating action of air and water, and 

 very many of them still preserve the surfaces they possessed at the time 

 of their deposition. Among the fragments of shale, large and small, it 



