368 GEOLOGY OF OHIO. 



Harrisville is one of the townships in which the water " divides " to 

 the' Ohio River and Lake Erie. The great marsh is drained in both di- 

 rections, and is much lower than most of the land along the "divide." 



The Cuyahoga shale is very finely exposed north of the village of Lodi, 

 many rods of abrupt river-bluff offering superior sections of this forma- 

 tion. Lime is quite rare in the rock here, and iron concretions are not 

 as abundant as in some of the exposures ol this shale in Medina. Fossils 

 in the soft shale are numerous, though difficult to preserve. Brachiopods 

 and bryozoan corals abound, and occasionally a crinoid or a trilobite may 

 be found. 



Quarrying has been carried on since 1840 in numerous places along 

 Whetstone Creek, a mile south-east of Lodi. The rock is chiefly an argil- 

 laceous sandstone, most of the beds being only a few inches thick, and 

 the thickest not twentj' inches. The exposures here are twenty- five to 

 thirty feet high Large crevices run through all the rock, which is badly 

 broken up. Many layers show something of a micaceous nature, and one 

 of an inch in thickness splits into thinly-laminated sheets of large size. 



Ahove the shale is a deposit of Drift-conglomerate but slightly cemented 

 together. This bed is four to five feet thick, and when cut into, usually 

 stands up against the weather, though in places it falls away verv quick- 

 ly. Large masses may be found in the ravine where they have stood 

 years of washing, and yet seem very compact and hard to break up. This 

 deposit of Conglomerate is largely made up of stones of the size of eggs, 

 and some are even large enough to weigh two pounds. 



One mile west of Bridgeport, the town just across the county line in 

 Wayne, there is a large quarry on the south side of the Killbuck River. 

 At this exposure the rock lies in thicker beds than it does along the 

 Whetstone Creek. I found in this quarry a large fish spine (Gyracanthus 

 compressus), also an abundance of fossil shells (Producing'). 



Travertine is being deposited in a lot owned by Col. Robert English. It 

 is a mile from Lodi by the north-east road. Some of the masses are large, 

 and they are quite numerous about the spring which issues from a hill- 

 side. 



The largest bowlder in Ohio, with possibly one or two exceptions, may be 

 seen in a field at the cross-roads, one mile and a half north of Lodi, and 

 a little east. This mass of erratic rock is that variety of granite called 

 syenite. The feldspar in this is dark flesh colored. These masses are of 

 metamorphic rock, unknown in Ohio except as bowlders. Like all such 

 granitic bowlders, these are fragments of Canadian rocks which were 

 broken from the hills and ledges where they belonged, and brought to 

 the south either by the great glaciers which once ground down the whole 



