I have failed to find even the slightest trace of shells in any 
of the drumlins south of Nantasket Beach. This is an instance, 
however, where negative evidence is of very little value, the 
apparent presence or absence of shells depending very largely 
upon the character of the exposure. A deep section is usually 
essential ; for, as Mr. Upham has explained, the shells are very 
likely to have been dissolved out of the upper, oxidized or 
weathered layer of the till. It is probably for this reason that 
they are not found in the shallow sections afforded by Point 
Allerton Little Hill, Little Hog Island, White Head, World's 
End, and Planter’s Hill, as well as all the inland drumlins. 
We may reasonably hope, however, that shells will yet be found 
in Green Hill and on Bumkin Island. That shells actually 
occur in the drumlins of Cohasset we have satisfactory evidence 
in the fact, to which my attention has been called by Mr. H. 
W. Nichols, that fragments of the round clam were found by 
Mr. Titus Burbank some years ago in digging a well near the 
summit of James Hill, northeast of Scituate Pond. The well 
is 45 feet deep; and the shells were observed only near the 
bottom. They cannot, therefore, be referred to any post- 
glacial source. 
Although shells are now so generally wanting in the buff or 
oxidized till, evidence of their former existence is afforded by 
the calcareous material which may, in certain cases, be detected 
in the till. This evidence is especially clear in the buff till of 
Telegraph Hill. The carbonate of lime has, in part at least, 
been dissolved and segregated, locally but firmly cementing 
the till, and forming in the finer parts regularly rounded concre- 
tions, from a fraction of an inch to several inches in diameter, 
which are sometimes attached to the flat surfaces of the large 
stones or bowlders. These nodules effervesce freely with acid, 
and no other source of the carbonate than the shells is apparent. 
Mr. Upham has correctly explained the shells in the till, 
which are always in a fragmentary form, as having inhabited 
the bottom of Boston Harbor before the coming of the ice-sheet, 
