Plastic Clay. 



199 



tiary, and in part diluvial, which lie between the Alleganies and the 

 ocean on the east, from Nantucket to Florida, as resting directly on 

 the inclined edges of the older rocks, and exhibiting themselves no 

 traces of dislocation."* But unless my senses have greatly deceived 

 me, we have on Martha's Vineyard most decisive evidence of dislo- 

 cation in one of the higher members of these deposites : for Dr. Mor- 

 ton has proved, that farther to the south, a part of the beds of this vast 

 formation are equivalents of the higher secondary strata in Europe, 

 If, therefore, the inclined position of the strata on the Vineyard be not 

 a solitary case, resulting from local disturbances, Beaumont's position 

 is untenable, and his inferences, dependant on that position, incorrect. 



In Truro. 



Truro is the extreme town but one on Cape Cod ; and on the east- 

 ern shore is a patch of plastic clay, large enough for one or two good 

 farms, and on which stands a light-house, as at Gay Head. The 

 clays here are somewhat variegated ; though the predominant color 

 is blue. They exhibit also, the same unstratified aspect, as at Gay 

 Head; and are, I doubt not, another remnant of the same formation. 

 I did not, however, give the spot that protracted examination which 

 would be necessary to ascertain the dip of the strata, and whether 

 they contain any organic remains : not being then aware that the for- 

 mation had such important connections as I now suppose it to have. 

 The spot deserves further examination. 



In Duxbury. 



Clay is not unfrequently found beneath the sands of Cape Cod; 

 though I am not aware that any cliffs of considerable height occur 

 except in Truro ; nor that any organic remains of interest have been 

 found in it. But in Duxbury, in Plymouth county, I have ascertain- 

 ed, since the publication of the first edition of the first part of my Report, 

 that strata and organic remains exist there, identical with those at Gay 

 I am much indebted to the Rev. Benjamin Kent, of that place, for Head, 

 communicating to me a very detailed account of these strata and rel- 

 ics, made out after personal examination. It appears that 30 years 

 ago, a well was dug near the edge of a plain of considerable extent, 

 about 4 1-2 miles from the sea, and nearly surrounded a by swamp. 

 Coarse gravel (diluvium) occupied the surface ; next came a layer of 



* Recherches, &c. p. 320, Chap. 1. 



