34 Experiments on the Adhesion of Iron Spikes, 
formation appears very deficient in mineralogical interest. I have 
not seen in it any minerals, except quartz and sulphuret of iron. In 
some places it furnishes good roofing slate, and I have been informed 
that a vein of limestone occurs in the rocks near Ticonic Falls at 
Waterville, but I had not an opportunity of examining this place. I 
have called the formation Argillite from its prevailing character, al- 
though in some places it resembles talcose slate, and at others gray- 
wacke. 
{ think it worthy of remark, that the valley of the Kennebeck, 
from Waterville, as far north as I had an opportunity of observing 
during my visit in 1832 to Mount Abraham, is covered with boul- 
ders of granite, of so peculiar a character that they may perbaps 
some day be traced to their original position. These boulders dif 
fer from those observed on the Penobscot, by containing large im- 
bedded crystals of white feldspar, which make the masses appear at 
a little distance as if they were covered with broad chalk marks. 
These crystals are generally about three inches long and one fourth 
of an inch wide. I have seen some, however, five inches long by 
four wide. 
I hope soon to be able to send you an account of the botanical 
observations which I have made in the vicinity of Waterville: in 
the mean time I send this hasty article, hoping that the few facts it 
contains respecting the geology and botany of the regions visited, 
will be received with interest, on account of the few notices which 
have hitherto been published upon these departments of the natural 
history of Maine. 
West Point, Aug. 31, 1836. 
Arr. Ill.—Experiments on the Adhesion of Iron Spikes of various 
forms, when driven into different species of Timber; by WaurER 
R. Jounson, Professor of Mechanics and Natural Philosophy im 
the Franklin Institute, Philadelphia. 
_In reference to rail-road constructions, bridge-building, and sev- 
eral other useful applications in civil engineering, as well as in naval 
ture, the adhesion of spikes, bolts and nails of various forms 
s an object of much practical i importance. Jn regard to rail- 
roads, peice is worthy of more attention than lupe at fest sige 
ce foes er a oe 
\ Fett Seay Boe 
era 
