138 EVIDENCE OF ELEVATION* OF THE SEA COAST 



Bed-rock (Triassic) sandstone outcrops in this brook, but 

 throughout the valley the stream has never deepened its bed 

 to any great extent. The drift lies scattered everywhere and 

 a number of boulders are well ice-scratched. 



The delta that lies a little way up the valley's mouth, has 

 experienced a large amount of sub-aerial erosion as well as that 

 done by the stream, although the characteristic flat top of the 

 delta is still to be seen, its surface is uneven in places, and as 

 the brook has cut longitudinally through, one can see that its 

 top-set and bottom-set beds are nearly horizontal. In other 

 places, owing to the growth of grass, I could not make out much 

 of its structure. Where the delta unites to the side of its valley, 

 its top is quite level or has a gentle down-stream slope. 



The other brook is about a mile to the west and flows almost 

 due north. Near the head of this gorge there appears more 

 drift and larger boulders are found. A little west of this valley 

 is a splendid example of glacial drift, probably the lobe of a 

 moraine. 



The delta in this brook is in a somewhat better state of preser- 

 vation than the other. Although time has marked it by erosion, 

 it still shows a flat top, and where the present stream has cut 

 its path through, one can see the bedding and imagine its former 

 shape. 



The material of these deltas is a fine calcareous, sandy loam, 

 and I think there is some evidence to show that it has been in 

 part derived from the boulder-clay over which these brooks 

 have run. 



As the beds of these brooks are above the marsh land, till evid- 

 ently lies below them, as it has been found below the marsh in 

 several places in this locality. 



Although the present streams are quite small, these valleys 

 seem too large to have been cut by the streams that now occupy 

 them. These valleys are about forty feet deep and several 

 hundred feet wide between the tops of their sides. However, 

 I think they are of recent origin and have been cut quickly by 

 swiftly flowing streams. 



I believe the history of these brooks and their deltas may be 

 found by piecing together the Post-glacial changes that have 

 taken place in this part of the country. The evidence seems 

 to show that these brooks began their flow after the final retreat 

 of the ice. It is admitted that at the close of the Glacial Period 

 the land stood a little higher relative to sea-level than it does 



