6 Quaternary Formations of Southern New Jersey. 



C is gentle, it, too, will be strewn with more or less debris in 

 transit from the higher to the lower plain. 



If now the conditions of the region are so changed that con- 

 siderable deposition takes place on the plain of degradation, CD, 

 we shall have the result shown in Fig. 2, where CD has been 

 aggraded to EF. The material deposited in the valley will be 

 designated formation 2. If the materials of formation 2 were 

 derived from the same sources as those of formation 1, and 

 deposited under similar conditions, they will be similar to them 

 both physically and lithologically, but more or less unlike the 

 slope detritus between B and C. The aggradation of the main 

 valley to the level EF will be accompanied by the aggradation 

 of all the side valleys, but the debris deposited in them may be 

 somewhat unlike that in the main valley, because derived from 

 more restricted sources, namely from the drainage basins of the 

 tributary streams. These streams may have made some contri- 

 bution to the deposits in the main valley, but a part of the de- 

 posits in that valley were brought in by the main stream. While 

 the valleys are being aggraded, waste from the slopes above the 

 valley bottoms may be accumulating on the surface between the 

 two plains (BE), wherever the gradient is sufficiently gentle. 



If erosion succeeds deposition, a new flat lower than EF will 

 in time be developed along the main stream, and harmonious 

 flats along its tributaries. Let it be supposed that these new flats 

 are developed at levels lower than those which preceded. The 

 result is illustrated by Fig. 3. On the plain GH, and on the slope 

 IG where it is gentle, there will be slight accumulations of 

 material, deposited as was that on the plain CD, and the slope 

 BC (Fig. 1) at an earlier time. In constitution, the materials on 

 the slope above G (Fig. 3), will be like those on the older and 

 higher slope BE, except that the formation y may have made 

 some contribution to the former. Meantime there has been more 

 or less shifting of the surface material between B and E. The 

 old has been carried on, and new has been washed down from 

 above and deposited, so that the detritus on this slope (BE) is 

 of all ages younger than that of formation 1, dating its age from 

 the time of its depositions. 



