GLACIAL DRIFT. 21/ 



in a westerly direction ; and this may indicate what sort of phenomena 

 should be looked for, in the other westerly descending valleys mentioned, 

 to satisfy us of the existence of tributary glaciers. No pains have been 

 taken to observe this class of facts. Oliverian brook in Haverhill may be 

 expected to show some signs of a local glacier descending the west flank 

 of Moosilauke. On page 30, considerations are presented to show that 

 unusually abundant gravel and sand deposits in Haverhill must have 

 been derived from such a source as this local glacier would be. We have 

 also a barrier-like ridge of till lying across the Oliverian valley suggestive 

 of a former terminal moraine. There are many boulders of Bethlehem 

 and porphyritic gneiss in the Oliverian valley, seemingly of eastern origin. 

 If not from the Moosilauke pile, they must have been brought down by 

 the main Connecticut Valley ice. The numerous marks between Haver- 

 hill and Carroll may be regarded as made by one branch of the Con- 

 necticut glacier. These are very abundant, and satisfactorily illustrate 

 the local movement. Those down the Passumpsic valley are less com- 

 mon and convincing. 



Above the Ammonoosuc district the Connecticut Valley movement 

 seems to have been interrupted in consequence of the presence of the 

 Gardner Mountain barrier. The markings in this part of the valley do 

 not conform to the topography, and must therefore be regarded as made 

 by the older movement. The map (PL H) illustrates the nature of the 

 ground over this space. Above Lancaster there are well marked signs 

 of a local glacier, probably the last movement in the region, separate 

 from and later than that just described. Its existence is manifested by 

 moraines and not by strias, and may be classed with the Bethlehem gla- 

 cier, to be described presently in the words of the late Prof. Agassiz. 



Midway between Stratford Hollow and North Stratford is a pile of 

 granite boulders so conspicuous as to arrest the attention of the most 

 careless. They occupy several acres of ground, and seem to form a ter- 

 minal moraine. It is represented in Fig. 53. The exact location is indi- 

 cated by the word Moraine on PI. I ; and a section crossing the valley is 

 shown in Fig. 2. Mr. Clough's stereoscopic view of the same is entitled 

 "New Hampshire Cow Pasture." The name indicates the use to which 

 the field is put, while the abundance of boulders seems to have discouraged 

 the owner from attempting to make a stone wall of the material. A 



