240 IRVING B. CROSBY 



and represent the opposite spur of the old divide. There appears 

 to be ample field evidence to prove that eastward from Mount 

 Winthrop Divide the drainage was into the Gulf of Maine, and that 

 westward it flowed to the Connecticut. 



This divide prevented the Androscoggin from flowing to the 

 east, as it now does, and the broad valley of the Upper Ammonoosuc 

 represents its course when tributary to the Connecticut. 



Of the three passes connecting the Upper Ammonoosuc and 

 Androscoggin valleys, either ^ or C offers a direct route without 

 sharp angles or reversals of direction. Pass A would necessitate 

 a much longer course with a sharp turn at Berhn, and it will not 

 be considered as the former route of the river. 



A river appears, therefore, to have flowed through the present 

 Androscoggin valley to Dummer, through pass C orB, thence down 

 the valley now occupied by the Upper Ammonoosuc, into the 

 Connecticut. The name "Mahoosuc River" is suggested for 

 this stream. 



Profile 2 (Fig. 2) shows the grade of this course, the full line 

 representing the present surface and the broken line the probable 

 bed-rock surface; and profile i (Fig. 2) shows the grade of the 

 present river. A comparison of these two profiles shows that the 

 former route has a fairly constant grade, a normal condition for 

 a large river, while the present course drops several hundred feet in a 

 series of falls and is characteristic of a younger river which has not 

 yet eroded its valley to grade. 



During the existence of the Mahoosuc River a stream from 

 Mount Winthrop Divide joined a stream from Mount Washington 

 and flowed north to the point where Berlin now stands, and then 

 through pass A into the Mahoosuc River. Three miles north 

 of Berlin was a low divide (D on Fig. 3) between the drainage 

 to pass A and a stream which joined the Mahoosuc River at Dum- 

 mer. Between divide D and Dummer all tributaries joined the 

 present river with retrograde courses; and at the time when 

 the stream in that valley flowed north instead of south, as at 

 present, these tributaries had normal junctions with the main 

 stream. The old drainage is shown in Figures i and 3. 



