Ce 
— 
RAYMOND: CORRELATION OF THE ORDOVICIAN STRATA. 247 
In ‘zone 2 the only graptolites are Amplexograptus vasae and Cory- 
noides curtus. 
Zone 1 contains Climacograptus scharenbergi and C. rugosus. 
In America the zone of Dicranograptus clingani, though that species 
itself is not present, is found in the shales of eastern New York and 
Canada. These shales were long called Utica, but Ruedemann 
(113 and 117) has shown that they are older and equivalent to the 
caleareous Trenton of Central New York. The shales are also 
involved in the mass of the so-called Hudson River shales in the Hudson 
Valley. They are the Cumberland Head shales of the Champlain 
Valley, the Snake Hill shales of the Hudson Valley, and the Cana- 
joharie shales of the Mohawk Valley. 
At Canajoharie, the type-locality for the formation of that name, 
Ruedemann (117) found the following sequence of faunas :— 
At the base, are seventeen feet of dark blue fossiliferous limestone 
with interstratified shale beds. This limestone is basal Trenton and 
contains the Cryptolithus fauna in the limestone, while the interstrati- 
fied shale afforded Corynoides calicularis, Diplograptus amplexicaulis, 
and Mesograptus mohawkensis, so that we here have an indication of 
the fauna of the shaly equivalent of the Glens Falls limestone. 
Above this comes the Canajoharie shale, which is strongly cal- 
careous in its lower portion, becoming truly argillaceous above. 
In the lower sixty-five feet of the Canajoharie, Diplograptus ampleai- 
~ caulis is the only graptolite, while in a zone between 65 and 120 feet 
above the base of the formation, Corynoides calicularis, Diplograptus 
putillus, and Lasiograptus eucharis are added. Brachiopods, pelecy- 
pods, and crustaceans are fairly common in both zones. In the zone 
from 115 to 150 feet above the base Glossograptus quadrimucronatus 
cornutus appears, associated with some of the previously mentioned 
graptolites. These pass up through the next 120 feet, to 270 feet 
above the base of the formation. Triarthrus becki is not noted until 
a height of 190 feet above the base of the formation, when it appears 
suddenly in great numbers. 
Thus, combining the information obtained from the Canajoharie 
and Sprakers sections — these localities are only about two and one 
half miles apart — Ruedemann made out four faunal zones. 
4. Zone of Climacograptus spiniferus, Diplograptus vespertinus, 
and Lasiograptus eucharis. 
3. Zone of Lastograptus eucharis, Trocholites ammonius, etc. 
2. Zone of Glossograptus quadrimucronatus cornutus, Corynoides 
calicularis, ete. 
