360 Geological Survey of the State of Ohio, 



at random over the bottom of the lake, estuary or sea ; so that a 

 jaw would be found in one place, a rib in another, a humerus in 

 a third — all included, perhaps in a matrix of fine- materials, where 

 there may be evidence of very slight transporting power in the 

 current, or even of none, but simply of some chemical precip- 

 itate.* 



With these remarks we take leave of the report of Mr. Briggs ; 

 we have r _ d it with pleasure and profit. 



We have described the div erent groups embraced in the report 

 of Mr. Briggs. We now proceed to describe those above. 



VI. Buhr. — This rock forms the dividing line between the up- 

 per and lower coal series. In our remarks upon Dr. Hildreth's 

 report, we gave the principal characteristics of this rock. 



VII. Upper coal series. — These, like the lower coal series, are 

 composed of sandstones, shales, coal, iron ores, and limestones. 

 The coal is the most valuable mineral in this group. There are 

 at least, four distinct beds, capable of being wrought, and of a 

 good quality. In this group, is included the cannel coal of Cam- 

 bridge, described in a former number of this Journal. The lime- 

 stones in this series, are more abundant than in the lower, and ex- 

 ert a beneficial influence on the soil. The Belmont Hills are noted 

 for their productiveness. The iron ores included in this group, are 

 not as abundant as in the lower series — ^nor are they wrought for 

 manufacturing purposes. The organic remains of the two groups, 

 do not differ essentially. In the limestones, we meet with the 

 Encrinite, Delphiniila^ Spirifer, Productus, Terehratula, &lq,. We 

 have detected no terrestrial plants. The sandstones often contain 

 the stems of coal plants. The most common are Stigtnaria ficoi- 

 •des, Lepidodendron Stei^nhergi 1 and several varieties of Sigil- 

 laria. From the shales, beautiful impressions are obtained. The 

 principal are Equiseta, Calamites, several species of Filices, and 

 LycopodiacecB, and perhaps, one or two species of Palmce. Two 

 or three species of Astorophyllites have been found. Fucoides are 

 not uncommon. 



VIII. Tertiary deposits. — Under this head, we place the prai- 

 ries or barrens, in the western portions of the State, the pebble 

 beds and boulders of primitive rocks, so abundant in some parts 

 of the Scioto valley, as well as those deposits, in which the 



»3. Lyell, Lond. Ed. 232. 



