AMERICAN SILURIAN CRINOIDS 
By frank springer 
ASSOCIATE IN PALEONTOLOGY, U. S. NATIONAL MUSEUM 
INTRODUCTION 
Western Tennessee has been classic ground for American paleontologists 
ever since Gerard Troost, State Geologist of that state, brought to the 1849 nieet- 
ing of the American Association for the Advancement of Science a series of 
fossil crinoids collected by him in Decatur and neighboring counties, and sub- 
mitted through Professor Louis Agassiz ^ an imposing list of genera and species 
new to science, of which he had prepared a monograph with full descriptions and 
numerous illustrations. For want of funds to defray the expense, the mono- 
graph was not published during the author’s lifetime, but remained buried until 
1909, when it was issued by the United States National Museum as Bulletin 65, 
the MS., together with the collection, having been left by Troost to the Smith- 
sonian Institution with a view to publication. By that time most of the new 
forms had been described by other authors, and the credit for the original dis- 
coveries announced in his list was lost to the one by whom it was so well deserved. 
In 1847 came the eminent German paleontologist, C. Ferdinand Roemer, 
who became deeply interested in the prolific fauna of the Tennessee Silurian, 
and during a sojourn of several weeks made extensive collections in Decatur 
County. The results of his researches were published in i860 in his well known 
monograph entitled “ Die Silurische Fauna des Westlichen Tennessee,” 4to, 
Breslau, Germany. Many new species were brought out, and the work has been 
regarded as a standard for the area of which it treats. 
The Tennessee A^'ea 
The region under consideration lies along the Tennessee river and within 
its drainage. It abounds in natural exposures in the bluffs of the river and its 
tributaries, and in numerous glades where the fossiliferous limestone was ex- 
posed on the surface and disintegrated by erosion of the softer overlying 
clays and marls. Fossils in great numbers were weathered out upon those 
glades, which produced the greater part of the specimens obtained by the early 
collectors. 
Following the two pioneers above mentioned. Prof. J. M. Safford as State 
Geologist made extensive studies of the Silurian formations, and his accounts 
1 Proc. Am. Assn. Adv. Sci. (2), VIII, read Aug. 1849, vol. 2, 1850, pp. 59-64. 
