74 J. Deane on New Fossil Footprints. 
of the products above this rock are throughout more or less simi- 
lar, while they differ from those below ; and, with a single excep- 
tion, lithological character is a sufficient guide for distinguishing 
the different strata.” mgs tM 
“'This contrast of character is more marked towards the west- 
em extremity of the district than it is farther east ; and, finally, 
on its eastern extreme, there is a great similarity in the lithologi- 
cal features. This change is likewise attended with the occur- 
rence of some of the fossils of the lower group in the rocks of 
the higher, the nature of the two being very similar, although 
the Tully limestone is in its greatest force; while at the west, 
where it does not exist, no such mingling of the fossils is 
known.” 
“ At Ithaca, for example, where we are far above the Tully 
limestone, and where the rocks are well marked by an abundance 
of fossils peculiar to themselves, still we find the Microdon bella- 
striata, Modiola concentrica and some others, and I have detected 
the Calymene bufo and Dipleura Dekayi in the same associa- 
tion. Still farther east there is a greater mingling of species of 
the lower rocks with the upper, and a nearer approach constantly 
in materials of composition. 'These circumstances, in the east- 
ern portion of the state, render it difficult to point out the line of 
demarcation between the lower and higher rocks of this division.” 
“At the eastern extremity of the state, also, the Tully lime- 
stone does not exist, and, therefore, that guide to the line of di- 
vision between the lower and higher groups is wanting: ) The 
absence of this rock, and the similarity of lithological products, 
as well as the mingling of organic remains of the lower rocks, 
renders it impossible to make a distinction in groups with the 
same degree of satisfaction as further west.” D, BD. Ov 
as et ae baa "(Tobe continued.) 
Pa aeror 1 Z H 
nstinasnlinisiaaat 
Arr. IX.—Notice of New Fossil Footprints ; by Jaues Deane. 
SeveraL new species of footprints of birds, and one of quad- 
rupeds, have been discovered at Turner’s Falls, during the past 
year, and like all others obtained at this remarkable locality, foe 
are singularly distinct, and through their configuration, we are 
enabled to determine the class of animals by which they were 
made. ‘The impress of the tarsus and phalanges, and of the der- 
moid and unguinal appendages is true to life, and their perfection 
Supplies us with the means of connecting the extinct with living 
races of animals. eo 
_ The new examples, three in number, are very beautiful ; the 
ot 1s comparatively long and slender, toes slightly diverging, 
and the stride of great extent, which indicates that the birds were 
