SOME GLACIAL WASH-PLAINS. 



107 



middle of the plain as given on maps is probably a fair 

 elevation to assume for water-level. 



Taking this level for data, we obtain the following re- 

 sults on two lines of wash- plains going north, one in the 

 Connecticut Valley area, the other in the Narragansett 

 Bay region. The elevations aie taken from the U. S. 

 Geological Survey atlas sheets. 



A. In the Connecticut Valley recfion. 



B. In Narragansett Bay region. 



If we suppose the two deposits cited from the Connec- 

 ticut valley area to have been formed at sea-level, we 

 must assume a postglacial tilting to the northward of 25 

 feet to the mile, a result so far abnormal as to exclude the 

 supposition. Moreover, this view forces us to hold to a 



ES8BX IN8T. BULLETIN, VOL. XXIX 8 



