508 LOCAL SECTIONS 
From Davenport to Rockingham the white compact limestone prevails nearly the 
whole distance, forming sometimes low perpendicular walls, four to ten feet high, 
and sometimes gradually sloping banks down to the margin of the Mississippi. 
The shores are here frequently lined with boulders, some of which are four feet 
in diameter. The hills rise to the height of one hundred and fifty feet, presenting 
a gentle inclination, with vegetation extending down to the water-level; so that no 
rocks are visible except in the above quarry. 
It is not until reaching a creek, half a mile below Rockingham, that the rocks 
can be studied. Here an argillaceous limestone crops out in thin shaly layers, nine 
feet above the water, disintegrating by exposure. In the debris, many good fossils 
can be found, of the following species: Atrypa reticularis, A. aspera, Terebratula 
concinna, Spirifer euruteines, S. granulifera, S. heteroclites, Orthis resupinata, Lep- 
tena inequistriata (?), Chonetes nana, Phacops macrophthalma, Favosites spongites, 
and £. polymorpha. 
At the mouth of the next creek emptying into the Mississippi, along with many 
of the above species occur, Olivanites Verneuilii, Phacops crassimarginata, Pleuro- 
rhynchus aleformis, Astrea ananas, and A, hexagonum. 
About three hundred yards up the first of these creeks is an outcrop of coal, 
enclosed between ledges of limestone of Devonian date, thus : 
1, Devonian limestone, eighteen feet. c, ’. Coal, nine feet above creek. ¢. Talus. s. Shale. 1’. D ian li t eleven feet. 
The limestone is hardly twenty feet from the coal, and rises, a little below, to the 
height of twenty-three feet. The coal is two and a half feet thick, and reposes on 
ash-coloured clay, with dark, thinly-laminated shale over it, six to eight inches thick. 
Fifty to sixty yards above this place, there is another coal exposure, occupying a 
similar fault in this limestone formation. At both localities the limestones contain 
fossils, the same as those previously enumerated as occurring in the ledges at the 
mouth of the creek. 
The coal is of inferior quality, being much impregnated with pyrites. Outcrops 
of the same seam of coal have been discovered at several other places in the vicinity. 
At New Buffalo, these limestones of the Devonian System are again to be seen, 
and are exposed for about five miles on the north side of the Mississippi, varying 
— from five to twelve feet in height, the hills back from the river being from seventy 
to one hundred feet in elevation; and one mile above Pine Creek, coal appears 
again, twenty inches in thickness, in the following relation to the associate rocks, 
No. 1 being the lowest. 
Feet. Inches. 
1. Limestone (ferruginous), containing Atrypa reticularis, A. aspera, 
Spirifer euruteines, and other Devonian species, i 20 
2. Light yellow clay, , : : 15 
3. Dark, thinly laminated shale, : : ' j 1 
4. Coal, : : ; ; : 90 
5. Coarse cat fine alsonks detaas not seen. 
