328 TRANS. OF THE ACAD. OF SCIENCE. 



noids, Synocladia, Pecten JSroadheadi (Sw.), (found only 

 here and in Group A,) Myalina subquadrata f Shum.), (prob- 

 ably its loAvest range,) some branching corals, Pinna (sev- 

 eral species), Pr. Pogersii ("Nor. & Prat.), Or. Missourien- 

 sis (Sw.), Allorisrna (several species). Pr. JYortcoodii does 

 not range below, nor does Pr. splendens (Nor. & Prat.) 

 above. Productus Pogersii is rare below, Orthisina Jlis- 

 souriensis rare above No. 169, but below it is often abund- 

 ant. A limestone occurs in Daviess and Gentry Counties 

 almost entirely made up of this beautiful fossil. In the 

 blue limestone of Daviess Co. I found fossil w r ood. Some 

 of the fossils of this Group, especially the Pryozoa, are of 

 Permian types. The lower stata pass northwardly from 

 Liberty landing through Caldwell, Daviess, and the middle 

 of Harrison County. 



Group G — Includes the rocks below the last as far as 

 Lexington, its base passing northwardly via Breckenridge, 

 Trenton, and northeastwardly. 



More than half this Group is composed of sandstone and 

 sandy shales. The limestones resemble each other both 

 lithologically and paheontologically, and abound in a small 

 Productus resembling the Pr. Wabashensis (Nor. & Prat.) 

 The limestones are useful for building purposes and for 

 making lime, and generally are of a light gray or whitish 

 color. A white oolitic limestone is found in Caldwell and 

 Mercer, which is highly esteemed as a fire rock. 



No bed of unlaminated clay has been found in Coal 

 measure series above this Group, and here it is first seen 

 lying beneath a bed of coal which is generally capped by 

 bituminous shale. The "Lexington Coal" occurs at the 

 base of this Group ; it varies in thickness from 1' 8" to 2' 4", 

 and is extensively worked. In the northern counties it be- 

 comes quite thin and is rarely seen. 



The limestone in Grundy is characterized by a vermicular 

 fucoid which often decomposes, leaving tortuous cylindrical 

 cavities in the rock, sometimes filled with oxide of iron. 

 This rock is the lower limit of Terebratula millepunctata 

 (Hall). 



Group IT. — This Group of 514' includes most of the re- 

 maining Coal Measure rocks of Missouri as far eastward as 

 Glasgow, thence northward by Huntsville and northward. 

 The beds of sandstone and shales are of great thickness; 

 the limestone is thin, often silicious and pyritiferous, and 

 contains but few good fossils ; some of the shaly beds 

 abound in Sjririgera, Orthisina Missouriensis (Sw.), Spiri- 

 fer cameratus (Mort.), Spirifer perplexits, Pro. costatus. 



This Group contains 14 workable coal beds, varying in 

 thickness from 1' to 4'. These coal beds are generally 



