HARVESTING FOSSIL SEA LILIES IN THE 

 OHIO VALLEY 



By R. S. BASSLER 

 Head Curator of Geology, U. S. National Museum 



The writer's field activities during 1932 were concentrated into 

 three weeks' investigation of certain Ohio Valley fossil localities which 

 had been under observation and preparation for collecting for the past 

 quarter century. Observations were also continued on silicification, a 

 subject which had interested him since 1908, when he published upon 

 the formation of geodes, those hollow spherical rock masses lined with 

 inwardly pointed crystals. 



The localities visited were noted for the crinoid remains yielded 

 years ago, so that the present exploration contributed chiefly to the 

 upbuilding of the Frank Springer collection of fossil echinoderms. 

 During the early part of this century, the writer, under the direction 

 of Doctor Springer, made extensive excavations in the Silurian and 

 Mississippian rocks of Kentucky and Tennessee to obtain fossil cri- 

 noids and other echinoderms. After every specimen in sight had been 

 collected the quarry debris was spread out in the hope that weather- 

 ing would in time expose additional examples. These old dump heaps 

 were revisited and carefully searched on hands and knees under the 

 hot sun of the past summer with the result that over 300 complete 

 crinoids and several thousand fragmentary examples were collected. 



Doctor Springer's old quarry in the Keokuk limestone near Craw- 

 fordsville, Ind., was first visited, but here it was found that expensive 

 digging would be unwarranted. Next the early Mississippian rocks 

 of Indiana and northern Kentucky were searched, especially in the 

 Knobstone area — the belt of country encircling the fertile Blue Grass 

 region of Kentucky, and crossing the Ohio River near Louisville, 

 into Indiana, where numerous conical knobs have been left by erosion. 

 Button Mold Knob, just south of Louisville (fig. 1), a typical ex- 

 ample of one of these wooded elevations rising above a plain of 

 Devonian limestone and shale, exposes the fossil-bearing rocks of 

 Early Mississippian age in a broad gash upon its southern slope 

 (fig. 2). Only a few of these layers are fossil-bearing, and intensive 

 collecting in the past seemed to have exhausted their possibilities. 

 However, trenches dug along them years ago now afforded some very 

 excellent crinoids. Here were discovered many geodes which had 

 formed from the infiltration of silica in fractured crinoid stems. 



