< 
STATE GEOLOGIST. 19 
shells, resembling in this respect the limestones of the Cincinnati 
series. Dr. Orton referred the formation, as shown in the Findlay well, 
to the Galena, Trenton proper, and Birdseye divisions.1. The total thick- 
ness of the Trenton in northwestern Ohio is unknown, but it exceeds 780 
feet. In the southwestern part of the state it is 650 feet, as shown in a 
well drilled on the McGhee farm in Liberty township, Adams county. 
This thickness is similar to that reported in Kentucky. 
The relation stratigraphically of the Trenton to the next important 
producer, the Clinton, is shown in the following record of Well No. 1, 
drilled on the Haines farm, near Roseville, Sandusky County. 
Feet 
DD GURVERSDI DC Meters cloleva crtevate sietep Sige cste rate 6 a wledete aielo bee 30 
( Grays MMe asec etsis oars iis nigie ack 140 
| Whi texslim ein i er are selene 160 
- Niagara series, ; BLE DINO \Ssycveravsve rene efetetens ete tecels 20 
White slate, first break...... . Os 
Brown lime, hard........... OAL 
Light slate, second break... 20 
ClintommlmMestone’ Feces sc cad ais Celele ec ccd ens wie sie yes 100 
MedinaaShales ered: sei. sci cleve cs chaeie'e ec « Beisleleisle sieiers 80 
Cincinnati series (white shales).........ccccceee 427 
Wticaashale  GDrOWwM)))\<sjsc sores iors oe cod cies elels coor ehei ee 2521 
PEPENCOM Ga TMEStTOME AU. cere coy c cieis clei cere ole ele leie eo eerslers 1,252% 
For comparison, a record is given of a well drilled on the Rohr farm, 
near Groveport, Franklin county, in the central part of the state: 
Feet 
OTE tack ebesasis payee rete ee cae oe o gla ete a ail or eiake ee rai alo abs 136 
OMIO TSN ATV OS er erepecscclas sock avevaiehsel nishctotecere: dione! Sia a eietonacaherel oe wie 167 
Corniferous limestone, top at..............cceccceee 3038 
Niagara limestone, bottom at..............2+000008. 980 
CUIMEOMES WAI ES ees erie rar eon ateeels ble ale Soo ene ie Sole eee ocele 5 110 
Clinton sand; shells only. atc. 22 3.0.5 5.6 bc oe oe 1,110 
MrentonwliMmestOnesat <seo4-sere cokes c vcs be Bee cis a eeews 2,146 
Bottom of well (in Trenton).............2ccccccees 2,675 
THE SILURIAN. 
The rocks of this age in Ohio are divided by Orton as follows :? 
Feet 
4, l.ower Helderberg limestone................ 50—600 
3.. Niagara limestone and shale..............06. 125—380 
De PCVINCON PLOUD sce oie deere eerey soe apes an 20—150 
Dee MeGdina SNALGs Seeccrouik oe or ooste and eaten Nike nib es 25—150 
1Geol. Sur. of Ohio, Vol. VI, p. 116. 2Ibid, Vol. VII, pp. 4, 5 
