312 EDWARD M. KINDLE 
is more striking than that of the stratigraphic break at the base of 
the Onondaga limestone, evidence of the latter is not wanting. 
Stauffer’ states that good-sized pieces of the sandstone containing 
Oriskany fossils may be found imbedded in the lower part of the 
cherty limestone, while at other places not far distant the Onondaga 
rests directly on the Silurian, with only here and there remnants 
of the Oriskany lying between. 
Ohio.—The fauna of the Columbus limestone, which has been 
listed by Stauffer,? affords satisfactory evidence that this lime- 
stone is the Ohio representative of the Onondaga limestone. The 
fauna, lithology, and stratigraphic relations of the Columbus 
limestone together furnish unmistakable evidence of its identity 
with the Onondaga limestone. The disconformity at the base of 
the Columbus limestone has been described by Dr. Stauffer as 
follows: 
The Middle Devonian of Ohio naturally falls into three divisions, of which 
the lowermost is known as the Delaware limestone and the upper as the 
Olentangy shale. This division is based on both lithological and faunal 
differences which in some respects are more apparent in the vicinity of Colum- 
bus, although not wanting in any of the belts of outcrop. ... . 
The base of the Columbus limestone rests upon the Monroe formation; 
this contact being that between the two great systems, the Silurian and the 
Devonian. There is thus a great time gap or unconformity, between these 
two formations, which is strikingly illustrated by the decided change in charac- 
ter and abundance of animal remains. In some localities the lowest layers 
of the Columbus contain an abundant fauna which in many respects resembles 
that of the upper part of the same formation, but where these lower layers 
have been observed in Franklin, Delaware, and Union counties, a basal con- 
glomerate is found which consists of large and small water-worn pebbles of 
the underlying formation imbedded in a matrix of Columbus limestone. 
Where this conglomerate is developed few fossils are found; probably because 
the organic remains, which existed in these localities at the time the layers 
in question were being deposited,~were ground to a shapeless mud by the 
continuous action of the waves among the pebbles of a rocky coast. This 
conglomerate was formerly supposed to represent the Oriskany sandstone of 
New York, and was so mapped by the geologists who made the first county 
reports, as well as by Newberry himself; but, since this basal conglomerate 
t Bull. Geol. Soc. Am., XXIII (1912), 373. 
2C. R. Stauffer, “‘The Middle Devonian of Ohio,” Bull. Ohio Geol. Survey, No. to. 
(1909), pp. 160-70. 
