MODIFIED DRIFT ALONG MERRIMACK RIVER. 81 
the high water of spring, forming the only extensive intervals on this 
river south of Plymouth. These are from a half mile to one mile wide, 
their fertility being in marked contrast with the barrenness of the 
“pine plains.” A fine view may be obtained in Canterbury and Concord 
from the edge of these plains, whose high bluffs descend abruptly a hun- 
dred feet, overlooking the level bottom-lands and the windings of the 
river for miles north and south. In other parts of its course the river is 
confined between terraces, which prevent an irregular route. Its mean- 
dering course here was signified by the aboriginal name Penacook, or 
crooked place, which was applied to the south part of this territory. 
Ancient river-beds are indicated at many places by shallow ponds, 
which lie in long and frequently curved depressions of the interval, often 
near the foot of the higher terraces, and but slightly elevated above the 
river. One of these is seen on the east side of the railroad, a mile south 
of Boscawen depot ; one lies on each side of the river just south of Sugar 
Ball bluff, near Concord; and others occur east of the south part of the 
city; but the largest and most interesting is Horseshoe pond, at the 
north end of the city, which is shaped like a crescent, being a half mile 
long, nearly as wide as the present channel, and six feet above the ordi- 
nary height of the river. This pond is crossed by the Northern Railroad. 
Its middle portion lies at the foot of a higher terrace, against which 
the river once swept its full current. The nearest point of the present 
channel is a half mile distant at the north, where the river bends and 
now directs its current against Sugar Ball bluff, a mile and a half north- 
east from Horseshoe pond. The date of these changes cannot be stated, 
except that it was before the first settlement here, 150 years ago. 
Recent Changes of Merrimack River in Concord. 
Dr. William Prescott, of Concord, in 1853 collected dates and measure- 
ments of many remarkable changes in the channel of Merrimack river 
which had taken place since a careful survey of this portion was first 
made in 1804.* From this record it appears that below Federal bridge, 
* Collections of N. H. Historical Society, vol. vii. At the time of publication of this volume, in 1863, a state- 
ment was added describing subsequent changes to that date. : 
In the same volume is also found a valuable address on “ The Valley of Merrimack,” by Joseph B, Walker, 
Esq., describing its physical features, and recounting its earlier and later history. ; 
VOL. UI. IT 
