273 
The thickness of the Stones River limestone increases as traced north- 
ward into Maryland and Pennsylvania reaching 1000 feet in the Mercers- 
burg-Chambersburg quadrangle. In these states it outcrops in elongated 
areas due to the great amount of faulting, folding, and erosion. Massive 
and thin-bedded limestones interbedded with magnesian layers and dove- 
1U. S. Geol. Survey Folio 170, p. 7. ; P 
colored purer limestones with considerable chert characterizes the formation 
lithologically. 
The following fossils identified from collections made at Guilford Springs. 
Pennsylvania, are from the dove-colored, cherty limestone members :? 
Girvanella cf. chazyensis. 
Tetradium syringoporides. 
Hebertella borealis. 
Hebertella vulgaris. 
Dinorthis cf. platys. 
Strophomena aff. charlottae. 
Maclurites magnus. 
Lophospira bicincta. 
Tsochilina cf. amiana. 
Ampyz halli. 
A comparison of this list with those from the Stones River group In cen: 
tral Tennessee indicates an equivalent age. 
Near Bellefonte, Pennsylvania, J. L. Collie* has referred 253 feet of fos- 
siliferous limestone to the Stones River. From the lower horizon of these 
beds Bathyrurus extans, Strophophema filiterta and Protorhyncha ridleyana 
were identified which correlates the bed with the Ridley limestone of Cen- 
tral Tennessee. The beds above were regarded as of Lebanon age from the 
occurrence of Lophospira milleri and the great abundance of Leperdita 
fabulites. Below the Ridley beds and above the highest fossiliferous horizon 
containing Beekmantown species, there are 2335 feet of unfossiliferous dol- 
omite the upper part of which may be equivalent in time to the Murfrees- 
boro and Pierce limestones of the Central Basin area in Tennessee. 
Eastern New York and Western Vermont. Through the work of Raymond 
and others upon the lower Chazy of New York and Vermont (Day Point and 
Crown Point limestones), there is made available a considerable faunal 
list which is published in Bulletin 92 of the United States National Museum. 
A comparison of the 64 species from the Day Point limestone with other 
Chazyan faunas shows that it is more closely related to the Appalachian 
Stones River than to the limestones of the interior area. Camarella longi- 
rostris Billings, Bumastus globosus (Billings) Bucania sulcalina Emmons, 
Hurychilina latimarginata Raymond, Holopea scrutator Raymond, Scenella 
pretensa Raymond, Stylaria parva (Billings) are characteristic Chazyan 
forms of the Appalachian-Champlain embayment and are found in the Day 
Point limestone of New York and the Lenoir limestone of eastern Tennessee. 
The Crown Point limestones apparently lie conformably upon the Day 
1U. S. Geol. Survey Folio 170, p. 8. 
“Geol. Soc. of Amer. (1908). 
