392 C. H. Hitchcock on Impressions on Clay. 
in n my father’s (Pres. Hitcheock’s) Final Report on the Geology 
of Massachusetts, as abounding in claystones of remarkable forms. | 
The impressions are principally found upon muddy deposits 
made by rains in the irregularities of the surface. The circum- 
stances in which these impressions occur, afford an admirable 
illustration of the manner in which similar oe were pr 
duced upon what is now solid rock. It is to be lamented that 
recent tracks were not more studied at tie time when it was 
doubted by men of science whether ichnolites were originally 
made by animals. In those days of discussion at least one of such 
doubters was convinced that the impressions were foot-marks, by 
noticing a piece of clay in the cabinet having on ita few tracks 
of asnipe. Though skeptics are now few on this subject, addi- 
tional confirmation of the facts and deductions of Ichnolithology 
may still be of value. 
Impressions of thirteen different kinds of animals have been 
noticed at this locality: viz., of man, four species of birds, two 
of quadrupeds, one batrachian, snails and annelids, besides two or 
three of a doubtful character. 
_ The human imprint is one of the most interesting. Jt isa 
¢ 
foot of the boy. All the strice se lines upon the sole of the 
foot appear distinctly on the specimens, particularly the fine 
strie and ri ~ The slime impressions and_ papilla 
the crow’s foot are also strongly marked. The difference be- 
tween the Sorbo of the foot of man and birds is finely ae 
hibited: in the former the lines are fhuch finer, and pa 
one another, running mostly across the foot ; while in the ieee 
the papille cover the whole phalanx with dots, scattered irreg- 
warly. 
The tracks which I have referred to the crow, may have been 
made by some other bird. It is a curious fact, that these tracks 
are frequently more difficult to refer to the true ani than 'Tri- 
assic* impressions. The most common track at this locality 13 
that of the common snipe, Tringa minuta. Iti is four-toed, and 
about an inch in length. In some places on the bed I have seen 
* Prof. Henry D. Rogers (see this volume, 123) has advanced reasons 
. for Saha thai tie euadstone of the Gohacotkes alley: belotge to tbo. Saremic 
er brother, also, (Dr. Edward Hitchcoek, Jr, of E. 
Hampton, M, ty cy pee = vered in this formation fine specimens of the 
Clathropteris, a genus of ferns confined in pe exclusively to Liassic 
‘He proposes to te dserite inthe following ober of thi Journal. But strong as the 
fe th nen is that the Liassic exists in this valley, I have pani it best 
Trias. The bem p at measurement of two i 
y father, shows a thickness of rock four times greater than either the Lias or 
him to conclude that probably several formations may 
