2Y0 Joseph Barrell. 



printing, thinking that he and the present writer would 

 find means of visiting Scotland. As this opportunity did 

 not come, he presented his views in 1916 in the paper 

 ''Dominantly Fluviatile Origin under Seasonal Rainfall 

 of the Old Red Sandstone." A copy of this was sent 

 to Professor T. G. Bonney of University College, Cam- 

 bridge, England, and his letter of thanks to Barrell 

 opened with the word '' Eureka." Truly we have here 

 the correct explanation of the origin of the Old Red 

 Sandstone. 



''The central conclusion reached in this paper is that 

 the Old Red Sandstone formations were not deposited 

 in lakes and estuaries, nor are they of desert origin." 

 They are ''river deposits accumulated in intermontane 

 basins," "exposed to air in times of drought," and 

 "similar to the basin deposits of the western United 

 States laid down in the Tertiary period between the 

 growing ranges of the Cordillera." "The Great Valley 

 of California may therefore in the present epoch, both 

 in physiography and in climate, be cited as a striking 

 illustration of the nature of the Old Red Sandstone 

 basins." 



Physiography. 



Previous to 1908, most physiographers held that the 

 fiat sky-line of the land seen in the southern ]3art of 

 the New England states represented a Cretaceous pene- 

 plain uplifted in early Tertiary time, but in 1912 Barrell 

 put forward a view long entertained by him, namely, 

 that not only was this plain not of Cretaceous age, nor 

 even of subaerial erosion, but rather that the supposed 

 plain is a series of seven sea-cut terraces, the result of 

 wave planation, made at different times during the late 

 Mesozoic and Cenozoic eras. This fundamental change 

 in interpretation was presented before the Geological 

 Society of America in 1912 under the two titles "Pied- 

 mont Terraces of the northern Appalachians and their 

 Mode of Origin," and "Post- Jurassic History of the 

 Northern Appalachians. ' ' Since then from time to time 

 Barrell had been working on this alternating series of 

 uplifts and strand-lines, and most of the time in the 

 laboratory mth topographic maps. On October 16, 1915, 

 he guided the New England Intercollegiate Geological 

 Excursion across four of these terraces, made since Mio- 



