316 GEOLOGY OF OHIO. 
GUIs) Yala aX ey aie Na) BEISISIN COLO | Gicouodod Gopaebos coddoodod odeGHb9K SobadUoNb osEGObOG0K0 L. 
Populus monilifera—Cotton wood ......... secs.+s CLP aR ENP ie a Ait: 
/ESculusielabras BUCKEYE enceeeteece eee eee PLO Eas Willd. 
Quwercustmackocanpa—— unt Oadkeer mee yacee eee eee een ee ae Michx. 
Populus grandidentata—Large-toothed ASPeM........06. sccseseee seceen veneee Michx. 
JELaomenDTS): JArraversieesiiae I ETO AD) ie. 40d) Soeoncdes eenocbtes soudsa usdoos bovonioora baoootent ds Marsh. 
ANGE1P) TAD OVALE M.—Shyyeah0y 9), ANEW Oke} S356 o0dd05 cooobecc) SockAosed Gobsedond Giouade0N pbaCo! L 
Fraxinus sambucifolia—Black Ash................ Eu siengeea dep ose wenlsecciancee Lam 
Gymnocladus Canadensis—Kentucky Coffee Bean..............00.. 00060 Lam 
PRUMUSWSerotina..blacke Chernyeneeeccercebteee cae seater eee nee hr. 
Populus tremuloides—Trembling Aspen .....2:.. ...c.c0s: cccossees coreeeooe oes Michx 
1 TRIBUS ied ea oy ea eet SU TREYS bl ao \ariase eacccuacronedes oncoos cobbds oceocs ecbuedeos odatée Sodom te L 
Cratecustomentosa— Blackeshonnysuwlernsssesneseeeeeteee eee Wei ce L. 
Ropuluss balsamuteraa—balmWlotiGruleadhecemnansensecectecess tena see see eae Ly 
Quercus palustris——brmy © a kiedcencsMeuceavcas eect sec ec caee ree eat aetna een DuRoi. 
Juglans cinerea—Butternut. [Seen only on the Van Wert ridge]... L. 
FAST MOTI GT ODA EWG waceecseuccrccche sccclees cca ayes se tere eae cae en eRe Dunal. 
GEOLOGICAL STRUCTURE. 
The rocks of the county belong to the Upper Silurian. The upper 
member of the Niagara, the equivalent of the Guelph of Canada, or of 
the Racine limestone of the West, is the lowest in outcrop in the-county. 
It underlies a tract of uncertain limit in the south-western part of the 
county, and is exposed in the St. Mary’s River, at Willshire. Over this 
lies the Waterlime, belonging to the Lower Helderberg. 
The former is a porous, magnesian limestone, of rather repulsive aspect, 
its naturally licht color being generally stained with iron-rust. In quar- 
rying it shows a blue color. It lies in thin beds of three to five inches, 
occupying usually the protected and most retired points of outcrop, owing 
to the rapidity with which it disintegrates under the forces of nature. 
The latter is, in Van Wert county, very similar in general appearance, 
but it has different fossils, and is harder. It is less porous. It has a 
drab color, but the color is lighter in Van Wert county, and in counties 
further north, than it isin Allen and Hardin counties, where it is often 
blue, or even becomes so bituminous as to be black and slaty. Its most 
slaty character is seen in Wyandot county. In Van Wert county, and 
also in Putnam, it is not slaty, or very rarely so, and shows very little 
bituminous matter. It burns to a very white lime in the township of 
Union, where there is a surface exposure, but in Washington township, 
near Delphos, it is thinner bedded and more bituminous, the lime also 
becoming darker. 
Niagara Limestone.—The only exposure of this stone known within the 
county is at Willshire, in the bed of the St. Mary’s River, and in a small 
