12 SMITHSONIAN INSTITUTION 



Marathon. Two weeks were spent in the Glass Mountains searching 

 for blocks suitable for etching. Many were obtained, and a fine col- 

 lection of hitherto rare species is confidently anticipated when the 

 limestone lumps are finally decalcified. 



Along the Tennessee River in Decatur, Perry, Wayne, and Hardin 

 Counties Silurian rocks are exposed in bluffs and glades. The same 

 rocks are also exposed in Perry County along the Buffalo River a 

 short distance east of the Tennessee. Although the high river bluffs 

 afford excellent opportunity for the study of the rock sequence, the 

 best collecting is obtained in the glades. These are generally open, 

 bare rock slopes supporting at best only a few cedars, and hence 

 are commonly known as "cedar glades." Occasionally these glades 

 are somewhat conical and are then known as "mound glades." When 

 a new glade, never before collected, is discovered, the geologist is 

 often rewarded by a fine harvest of specimens. 



Altogether 3 weeks were spent in west Tennessee collecting 

 Silurian fossils. First the exposures on the west side of the Tennessee 

 River in Decatur County were visited, then working from Linden, 

 the writer visited collecting places in Perry County. The work on 

 the Silurian was brought to a close with a few days of collecting in 

 Hardin and Wayne Counties. Many fine and some rare specimens 

 were obtained in these regions. 



At Murfreesboro in central Tennessee, the writer was joined by 

 Dr. Josiah Bridge of the United States Geological Survey. A joint 

 study of the Ordovician (Stones River) limestone was the object 

 of the meeting. These limestones form the lowest exposed part of 

 the Paleozoic column lying inside the "Central Basin of Tennessee" 

 and are surrounded by a rim of Silurian, Devonian, and Mississippian 

 rocks. Bridge and the writer were chiefly interested in collecting the 

 fossils and studying the sequence of layers of four formations — the 

 Murfreesboro, Pierce, Ridley, and Lebanon limestones that make up 

 the Stones River group. A fine collection of Murfreesboro fossils was 

 obtained at the excavation for a new armory on the bank of Stones 

 River just west of town. Good fossils were obtained from the other 

 f ormations, but the best collection taken came from the Lebanon lime- 

 stone exposed in a new cut on U. S. Highway 41 about 9 miles south- 

 east of Murfreesboro. 



The 2 months' collecting resulted in an abundance of much-needed 

 Pennsylvanian and Permian fossils from Texas and many good speci- 

 mens of Silurian and Stones River fossils from Tennessee. 



