240 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Field and the writer, a zone of dark limestone, containing such typical 
Leray (Black River) species as Columnaria hallt and Maclurites logani, 
is followed by more argillaceous limestone containing Echinosphaerites 
and a large number of other fossils. Christiania has not yet been 
found in the Bellefonte section, but this section does definitely show 
that the Echinosphaerites zone is there younger than the Leray — 
Black River of New York. As shown by Mr. Field, there is essential 
agreement between the section at Bellefonte and that at Chambersburg 
and Strasburg, so that all three of these occurrences of Echinosphae- 
rites may be dated definitely as post-Leray. 
According to Ulrich (119), the Kimmswick limestone at Thebes, 
Illinois, and Cape Girardeau, Missouri, has at the top a bed of erystal- 
line limestone, from five to thirty feet in thickness, which contains 
Echinosphaerites and Comarocystites, among other fossils. The 
Kimmswick at this locality can not be definitely placed in the section, 
except that it is post-Lowville. In the Nashville dome in Tennessee 
a formation correlated by Ulrich with the Kimmswick and containing 
Echinosphaerites has been found at Aspen Hill, where it is forty feet 
thick, and followed by the Hermitage, the Bigby, and the Catheys 
formations. The contact with the underlying formation is not shown 
but Ulrich states that there is no doubt that it rests upon the 
Carters, which is the equivalent of the Leray or Lowville of New York 
so that it may safely be stated that here again the Echinosphaerites 
bed is post-Leray. At this locality we have the Echinosphaerites 
without Christiania, and the zone apparently corresponds to the lower 
zone at Chambersburg, Strasburg, and Bellefonte. In this case the 
formation containing the Echinosphaerites is limited above by the 
Hermitage formation, a formation which can not be correlated with 
any New York formation, but which corresponds to the Logana of 
Kentucky and is also found at Bellefonte above the zone of Echino- 
sphaerites. The Hermitage is followed above by the Bigby limestone, 
which contains a fauna corresponding to that of the Prasopora zone, 
or Middle Trenton of New York and Ontario. The Kimmswick lime- 
stone, and the corresponding Echinosphaerites zone in Pennsylvania 
and north-central Virginia, may therefore be correlated with some 
confidence with the lower part of the Trenton of New York. 
The other occurrence of Echinosphaerites in the Appalachian region 
is in the Ottosee formation of southwestern Virginia and eastern 
Tennessee. Dr. Ulrich believes that the Ottosee is older than the 
Lowville, and, if this can be shown to be correct, then this zone is 
older than the two already discussed. A good section showing the 
