186 F. G. Clajyp— Clay of Probable Cretaceous Age. 



at Martha's Vineyard,* and Miocene greensands have been 



noted at Marshfield, 25 miles southeast of Boston. f In 1905 



Tertiary deposits were identified by Mr. Bowman at Third 



Cliff, Scituate, 20 miles southeast of Boston, underneath 



drumlin till and earlier glacial deposits.:}: As Tertiary and 



Cretaceous deposits were once of considerable thickness in this 



region, it is not improbable that future well-drilling may 



reveal them below sea-level at points farther north on the 



New England coast. 



U. S. Geological Survey, 

 Washington, D. C. 



* References in N. S. Shaler's Report on the Geology of Martha's Vine- 

 yard, 7th Ann. Rept., U. S. Geol. Survey, 1888, pp. 303-363. 



f Edward Hitchcock : Final Report on the Geology of Massachusetts, 

 vol. i, p. 91-95, and 427, 1841. 



% Isaiah Bowman, Pre-Fleistocene deposits at Third Cliff, Massachusetts. 

 Science, vol. sxi, June 30, 1905, pp. 993-994 ; and (for more complete con- 

 clusions) this Journal, vol. xxii, Oct. 1906, pp. 313-325. 



