1 62 STKATIGRAPHICAL GEOLOGY. 



Crawford and Fabyan houses, along the raih'oad, there are numerous 

 exposures of one or the other of these two granites. They do not extend 

 far up the side of the range to the west, where they join the Conway 

 granite, for the whole way. Other facts concerning this area are stated 

 upon page 137. 



Concerning the streams flowing westerly from the main range of presi- 

 dential summits, it may be proper to mention, that, as very few of them 

 are distinguished by any appellation, I have designated them by the name 

 of the mountain they spring from, both upon the map and in our descrip- 

 tions. The well-established name is Ammonoosuc, which starts from 

 the Lakes of the Clouds. Then we have Monroe, Franklin, and Pleasant 

 brooks. The Ammonoosuc passes the station, giving it a name. Monroe 

 crosses the turnpike a short distance west of the station. Franklin and 

 Pleasant unite quite far up. We have also used the name of Jefferson 

 brook for the second stream north of the mountain railway. 



Mt. Tom and Cascade brook. Passing up Cascade brook for about three 

 fourths of a mile, there is a foot-path designed for observing Beecher's 

 cascade ; and at the upper end a fine view may be obtained of Mts. 

 Pleasant, Monroe, and Washington. For this distance we conceive the 

 rocks belong to the Montalban series. It is very granitic, penetrated by 

 several systems of joints. Silica is abundant, seemingly finely diffused 

 through the mass. The rock partakes somewhat of the character of that 

 excavated for the railroad at the Notch, but more of that in the Ammo- 

 noosuc plain, just noticed. Of the nearly vertical seams we find low down 

 the courses east and west, north and south, north-west and south-east, as 

 well as north-east and south-west. These predominate in the lower se- 

 ries of falls. The main fall, figured in Volume I, page 305, exhibits the 

 north-easterly course, the stream having worn a deep, flume-like passage 

 for itself out of the granite. A more remarkable set of joints begin 

 to display themselves above the principal cascade, dipping easterly from 

 five to twelve degrees. They seem to exist in greater perfection the 

 further we ascend from the Crawford house. The first ledges seen have 

 been excavated irregularly; and numerous narrow branching granite 

 veins ramify in various directions, though notably in the same direction 

 with the stream. There is also a dyke of trap two or three feet wide, 

 with a course east of north. The u^oper seat marks nearly the western 



