A. E. Verrill—Post-pliocene fossils of Sankoty Head. 367 
ering, just as similar shells often crack into angular fragments 
in the dry heated air of our museums. Many of the entire 
specimens of the fossil quohogs, etc., show such fractures ex- 
tending in different directions across the shell, so that they are 
ready to break up into several angular fragments under the 
least strain, or even by a change in the moisture or tempera- 
ture. This condition of fossil shells is a very frequent one in 
other localities, and will account for very many cases where the 
shells are found broken into angular fragments in rocks o 
other periods. It is evident, both from the condition of the 
shells in the lower bed and from the peculiar assemblage o 
southern species, that it was deposited in the very quiet waters 
ofa sandy sheltered bay, entirely, protected from the action of 
the oceanic waves. re of species is similar to 
that now living in the protected bays of Southern New England 
at the depth of 8 to 5 fathoms The quohog-clam, oyster, 
Modiola hamatus, Cumingia tellinoides, Arca transversa, Urosal- 
pine cinerea, and the three species of Crepidula are the most 
abundant and characteristic shells. 
The Serpula bed consists mainly of convoluted masses of the 
tubes of Serpula dianthus V., mixed more or less with sand, but 
Without many other fossils. This Serpulc is still abundant all 
water is not brackish, from low-water to 8 fathoms or more. 
It is often particularly abundant on oyster-beds, and in such 
localities often completely overgrows the shells, if neglected for 
Ww: 
have the appearance of those shells thrown on the outer beaches 
by the Ha 
storms. The abundance of northern forms, such as uccinum 
undatum, Ceronia aretata, 
Mya truncata, Balanus porcatus, ete., shows that the bed was 
*That the depth could not have been less than 3 fathoms is probable because 
those species that abundantly inhabit the eel-grass (Zostera), which grows in shel- 
tered localities at all depths down to about 24 fathoms, are either rare or entirely 
absent, viz. Bittivm nigrum, Astyri ijoris nigrocincta, ; 
: rudis, Pecten irradians, ete. That the depth was probably not above 5 
fous toms, I infer because the quohog and oyster, when adult, are seldom 
‘™ any abundance below 5 fathoms. 
