142 THE INTERPRETATION OE THE PALEONTOLOGICAL CRITERIA 



abundant in the waters south of Cape Cod. This locality was early vis- 

 ited and described by William Stimpson. 1 Packard 2 also mentions the 

 same occurrence and refers to the fact that at "this point the Acadian 

 fauna seems to have merged into a more southern assemblage of animals." 

 The fossils are a good deal water-worn and " occur in the upper part of 

 the stratum of blue clay and pebbles which crop out from under the 

 coarse drift." The species recognized at Point Shirley which likewise 

 occur in the Maryland Pleistocene include the following: Nassa trivit- 

 tata Say, Ilyanassa obsoleta (Say), Urosalpinx cinereus (Say), Mya 

 arenaria Linne, Venus mercenaria Linne, Aligena elevata (Stimpson), 

 Ostrea virginica G-melin. 



Another and even more interesting locality is that of Sankoty Head on 

 the island of Nantucket which was early examined and described by 

 Desor and Cabot. 3 An abstract of the article by Desor and Cabot was 

 later printed by Packard. 4 A much fuller description of these deposits 

 was given by Verrill in 1875. 5 Two distinct fossiliferous 

 beds are described and the statement made that they " contain very dif- 

 ferent assemblages of fossils and were deposited under very different 

 circumstances; the lower bed contains such southern species as now in- 

 habit the warm, quiet waters of sheltered bays on the southern coast of 

 New England and farther south; while the upper bed contains many 

 northern species, many of them fragmentary and beach-worn, and all of 

 them, with one unimportant exception, the same species that are now 

 found cast upon the outer beaches of Nantucket and Cape Cod by storms, 

 and living in the colder outer waters, off the same coast." 



Later Merrill 6 prepared a detailed section of the beds and gave a list 

 of the fossils. Subsequently Cushman 7 discussed the significance of the 

 faunas of the several beds and pointed out the fact that there are four 



1 Proc. Boston Soc. Nat. Hist., vol. iv, p. 9, 1851. 



2 Memoirs Boston Soc. Nat. Hist., vol. i, p. 251, 1865. 



3 Quart. Jour. Geol. Soc. London, vol. v, p. 340, 1849. 



' Memoirs Boston Soc. Nat. Hist., vol. i, pp. 252, 253, 1866. 

 °Amer. Jour. Sci., 3d ser., vol. x, pp. 364-375, 1S75. 

 °N. Y. Acad. Sci. Trans, vol. xv, pp. 10-16, 1896. 

 7 Amer. Geol., vol. xxxiv, pp. 169-174, 1904. 



