ROSS COUNTY. 645 
corals, univalve shells, and chambered shells. The beds on Paint Creek, 
for a dozen miles below the last named point, are occupied very largely 
by casts of Megalomus. This remarkable fossil occupies nearly, or quite, 
ninety feet of limestone, near the mouth of the Rocky Fork of Paint. 
As the Helderberg limestone is followed to the southward and ecast- 
ward it is observed to thin out very rapidly. An excellent section—one 
of the best in this whole region—is found on the banks of Buckskin 
Creek, two miles north of Bainbridge, on the Greenfield road. The 
Megalomus beds of the Niagara, the Helderberg (waterlime), and the 
Huron shale are all shown in a section of fifteen feet. In other words, 
the Megalomus beds reach up almost to the shales—a thin wedge of Hel- 
derberg alone separating the two formations. 
It will be remembered that a few miles to the south-westward the 
Helderberg disappears in places entirely, the Huron shales lying upon 
the Niagara strata. The uppermost member of this formation at this 
point is a peculiar sandstone, which has been described as the Hills- 
borough sandstone. There are a few exposures of this sandstone in Pax- 
ton township, in the vicinity of the caves of Rocky Fork. 
We find in the great exposure of limestone at the Falls of Paint, in 
the beds that underlie the Megalomus division, another of these fossils 
above named in equal abundance. The casts of Pentamerus oblongus here 
make up the very substance of the rock. 
As Paint Creek turns in the extreme south-western corner of the 
county abruptly to the north-east, the heavy easterly dip of the lime- 
stones soon buries them below the surface. Their last appearance is op- 
posite the village of Bainbridge. 
An admirable general section of the rocks of the western side of Ross 
county is furnished by Bonner’s Hill, in the same neighborhood. The 
summit is five hundred feet above the valley, and the following scale— 
the formations being represented in their true order—is shown in the 
steep ascent: 
Feet. 
Upper beds of Waverly group (Buena Vista division, etc.) ..........0. esseese 42 
Wiavenlyaplack(slateme cms: setscccestescursecscccuscen sccetauiecy tem scu reece sation ccs 15 
NAVD CT hyaG MAE VACOULSER ss steiees ree ceduae cn sseeaede aunty, tua aR aMnL LEMURN AY AS 
VV eST@TE NZ BIMAIIES!. 06 coogos cadens xdbododk. Boudde0c0 GoHoTe Hdaded adgdeo Sdb600050 OOS NEd Som OASIBENRE AONE 50) 
Pel RO MES Males OMe Mee RCRD ARI LC eS LOE De A Nee SOU a noe Sena bea Wa Lo 332 
elder benavlimlestomen(waterlime) a. yd-.cinccscesssieedeeaiondnae'seseve\teackeises ow oe dies 15 
Miacanamumestoner (MeralomiusidiviSiom)s.sccesesesscactescescesedewecececsecasocees 15 
Both of the limestones here shown are capable of furnishing an un- 
limited supply of lime of the highest quality. It is not, indeed, sur- 
passed in whiteness, mildness, and durability by any lime of the State. 
