SUPPLEMENTAL EEPORT — HOCKING VALLEY 823 



In the Coal Measures of Ohio there are several layers of fossiliferous 

 limestone tound near seams of coal, which are very useful in aiding the 

 geologist in determining the coal seams. Coal seams were formed of the 

 vegetation of broad horizontal marshes, generally near the sea level. If, 

 when the land had settled below the water, and the material for a layer 

 of limestone had been spread on the surface of the buried marsh, that 

 limestone, thus formed, would have a regularity borrowed from the regu- 

 larity and evenness of the underlying floor. It is not unusual, however, 

 to find such a limestone separated from the coal by several feet of shale. 



Taking for our base the Maxville limestone, as developed in various 

 parts of Perry county, we find about eighty feet higher a limestone with 

 a thin coal seam under it. In the northern part of Muskingum county, . 

 I have met with a fossiliferous limestone between these two. From 

 twenty to thirty-five feet higher is a limestone, often flinty, under which 

 is a thin coal. About forty feet (possibly sometimes a little more) is 

 another limestone, found in the Putnam Hill, opposite Zanesville, which 

 is called, in the reports, the Putnam Hill Limestone. There is generally 

 a seam of coal under it. This limestone is usually from seventy-five to 

 eighty -feet below the Nelsonville seam of coal. I have recently found 

 it near Straitsville, seventy-two feet below the Great, or Nelsonville, 

 seam. Between the Putnam Hill limestone and the great 'seam, or from 

 thirty to forty feet below the latter, we find, sometimes, a thin lime- 

 stone with flinty tendency, on which rests the Baird ore found in the 

 hills west of Straitsville. This ore appears to have its place at the bot- 

 tom of the white sandy clay underlying the coal seam next below the 

 Nelsonville seam. Besides these lower limestones, there are two between 

 the Nelsonville seam and the horizon of the Pomeroy coal, one called the 

 Ames limestone, about one hundred and forty feet below the Pomeroy 

 seam, and another, called the Cambridge limestone, about eighty-five 

 feet lower. There is another fossiliferous limestone a little below the 

 latter, and I ha^ve also met with one in more eastern counties, between 

 the Pomeroy seam and the Ames limestone. There are, possibly, other 

 fossiliferous limestones, but the above-mentioned are the leading ones to 

 be found in Perry county, and in the portions of Hocking and Athens 

 included in this report. Besides these, there are many other limestones 

 which are not fossiliferous, except, perhaps, to a very slight degree. 

 One of these has its place perhaps sixty feet above the Nelsonville seam, 

 and from it several furnaces obtain their limestone. An earthy buff" 

 limestone, often nodular and ferruginous, comes in sometimes a few feet 

 above the Nelsonville coal. Another limestone is often seen a little 

 above the Bayley's Eun coal, and an additional one sixty to seventy feet 



