MArorrix corNTY. 295 



of Coops' Mound, and extending down to the bridge on the Hillsborough 

 road. The succession or relative position of the beds is as follows: 



Xo. 1. Light yellowish-gray nodular limestone 5 to 8 feet- 



X. 0. Bituminous shale 1 



Xo. 3. Gray shale 17 



No. 4. Soft coal. No. 11 1 



Xo. 5. Shale with iron pebbles. .-- 7 to 8 



Xo. 6. Chocolate colored coarse limestone 2 to 3 



Xi>. 7. Green and yellow shales 2 



Xo. 8. Black shalf and poor coal, Xo. 10 2 



X>. 9. Green and gray shale 3 to 4 



Xo. 10. Carlinville limestone 6 to 12 



At Fullerton's mill, on Macoupin creek, eight miles north-east of Car- 

 linville, on the north-east quarter of section 16, town 10, range 6, there 

 i^ an outcrop of light-gray, irregularly bedded limestone in the banks of 

 the creek, that I am inclined to refer to No. 1 of the above section, 

 although none of the underlay ing beds were exposed at that point. The 

 rock is similar in color and general appearance, and contains the same 

 species of fossils, mostly Athyrls subtilita, Product us UnunspintUj Rhyn- 

 choneUa Oxaijcnsis. Tercbratula bovidens, and joints and plates of Crinoidea. 



Just below Corr's mill, about four miles a little north of east from Car- 

 linville, the lower limestone in the foregoing section appears in the bed 

 of the creek, and between this point and the bridge on the Hillsborough 

 road the beds intervening between these two limestones are partially 

 exposed at several points. The chocolate colored limestone (Xo. 6) is a 

 coarsely granular rock made up in good part of the joints and plates of 

 Crinoideaj but it also contains Pinna per-acuta, Product us P ratten ianus 

 P. Xebrttxt-ritxix. and the teeth of several species of fossil-fishes, among 

 which we recognized Petalodus destructor and Cladodus tnortifer. In the 

 yellow-clay shale underlaying this limestone, specimens of Syringopora 

 innlt-aiU-nuata were quite common, and were frequently met with in the 

 rubbles of the creek bed. The thickness of the shales Xos. 7, 8 and 9 of 

 the foregoing section seemed to be quite variable in this vicinity, and at 

 some points probably attain an aggregate of fifteen to twenty feet, but 

 at the best exposure we were able to find they only measured about eight 

 feet, and at some points were still less. The chocolate colored limestone 

 of the above section seems to be identical with that of Sugar creek 

 in Sangamon county, seven miles south of Springfield, where the rock 

 for the old State House was obtained. The thin coals Xos. 4 and 8 of the 

 foregoing section are nowhere thick enough at any of the exposures seen 

 to be of any economical value. It is probable these beds underlie the 

 surface deposits over nearly the whole of the eastern tier of townships in 

 this county. Over a large portion of the two central tiers of townships 

 the Carlinville limestone forms the bed rock, while the western is mainly 

 underlaid by the sandstones overlaying Xo. 7 coal. 



