434 W. W. Dodge—Lower Silurian Fossils in Maine. 
should be supplied. I have planned two forms of apparatus 
and two series of experiments for this purpose; but the mak- 
ing of a more perfect eudiometric apparatus than had heretofore 
been used, the carrying on a series of daily analyses in dupli- 
cate of samples of air collected at this place, and the providing 
for the collection of samples at other parts of the continent, 
have used so much of my time and income that so far it has 
been impossible to carry out these plans. I hope before long 
to supply this deficiency. 
Art. LVI.—Lower Silurian Fossils in Northern Maine ; 
by W. W. Dopeée. 
THE writer found graptolites in black shale in No. 3 town- 
ship, of Range VII, Penobscot county, Maine, in September 
last. The fossils are, for the most part, mere bright films 
upon the dark rock, and in the small quantity of material 
brought away, but one or two individuals are sufficiently dis- 
tinct and entire for identification. e fragments are of at 
least four varieties; the Diplograptus type predominates. 
The most complete specimen is one of Diplograptus pristis, 
but of this the upper end of the axis is broken awa h 
cellules are about sixteen to an inch in each rank. Instead of 
narrowing gradually from end to end, as the drawings usually 
represent, the stipe retains its full width for an inch and a 
half and then its edges approach each other rapidly in the next 
half inch toward the solid, acicular radicle. 
A clearly-marked fragment, three-eighths of an inch long, is 
of a width only half that of the preceding, the axis is muc 
more distinct, the cellules, twenty-four to an inch on each 
side, although separated from one another nearly to the base 
by a rounded interval of about one-third their own width, are 
so shaped, with the denticle turned inward, that the appear- 
ance of serration in ‘the stipe is subordinate to its linear, par- 
allel-edged aspect. The general shape of what is visible is sug- 
gestive of aplolithus rampsus, although no _ bifurcation 
appears. Close beside this is a branching fragment upon 
which no cellules are discernible, probably its stem. 
One or two small, broadly-ovate shapes, perhaps Phy/lo- 
graptus, and a few long, slender stems not sufficiently charac- 
teristic, or too incomplete, for their relations to be ascertain- 
able, conclude the list of forms at present in hand. 
‘The shale in which these remains are embedded is probably 
