INTRODUCTION I I 



find weathered specimens of the more usual species. But it was the local collectors, who 

 understood the strata and could watch the quarries when rich layers were opened, or quarry 

 for themselves in favorable spots, by whom were found the bulk of well-preserved specimens 

 which made the locality famous ; many of the fossils with their light color and delicate mark- 

 ings appeared as if freshly dredged from the sea. In this kind of truly scientific collecting 

 Wachsmuth was past master, and he took great pride in it to the last, insisting that to under- 

 stand fossils best one must know them in the rocks. His knowledge of strata was almost 

 uncanny ; so that he could often tell when a rich layer was about to be uncovered in a quarry 

 and make arrangements for securing its contents. It was the current belief among the quarry- 

 men that he possessed a sort of second sight for good fossils that was not shared by other men. 

 There were other good collectors also, and a number of fine individual collections were from 

 time to time accumulated, most of which eventually passed into my hands. During the last 

 10 years of his life, in order to escape the trying climate of early spring, Wachsmuth went to 

 the south every February accompanied by his devoted wife, who was an ardent collector also, 

 collecting at many localities in Kentucky and Tennessee, but principally in the vicinity of 

 Huntsville, Alabama. He thus made immense collections in the later formations of the Lower 

 Carboniferous — Keokuk, St. Louis and Kaskaskia — many of them by quarrying after tracing 

 the crinoids to their layers, by which means he obtained unweathered specimens in a condition 

 of perfection that no one had seen before. 



Of the earlier collections at Burlington, three went to the Museum of Comparative 

 Zoology at Harvard, viz., those of B. J. Hall, W. H. Barris, and Wachsmuth, all made prior to 

 1874, and containing many types of species described by James Hall, and by Meek and 

 Worthen. With the exception of these, and occasional small lots obtained by visitors, and 

 scattered through the museums of the world ; one small but very choice series secured by the 

 British Museum ; and a small collection by the Field Museum, Chicago ; — the present collection 

 contains substantially all the fossil echinoderms that have been collected at Burlington and 

 vicinity during the past 50 years. It is derived from the following sources : My own personal 

 collections made from 1867 to 1872 ; that of Wachsmuth and of Wachsmuth and myself jointly 

 after 1874, including the product of frequent expeditions to other Burlington and Keokuk 

 localities in Iowa, Illinois, Missouri and Kentucky, and continual purchases from quarrymen 

 and small local collectors who usually brought their finds to Wachsmuth for inspection ; the 

 original collection of Dr. Charles A. White made before 1866, containing types of species 

 described by him and by James Hall, disposed of to the University of Michigan and subse- 

 quently acquired by me through exchange ; the early collections of Dr. Otto Thieme, Enoch 

 May, J. W. Giles, James Love, H. Griffith, S. Bittner, and an especially fine one of later years 

 of Mr. J. O. Beebe; collections made by myself at intervals from 1896 to 191 1, especially 

 through extensive quarrying at various points by a regular collector during several years, 

 resulting in important new acquisitions. 



From the so-called Knobstone formation, equivalent in part to the Lower Burlington, 

 important collections were made in southern Indiana, the Knobs of Kentucky, and at White's 

 Creek Springs, Tennessee, by Wachsmuth, and afterward extensively by Braun ; to which 

 must be added two choice sets of the crinoids of that formation given to me by Dr. Karl 

 Rominger, of Michigan, and Rev. H. Hertzer, of Ohio, both containing specimens of much 

 importance especially in the Flexibilia. 



Foreign equivalents. From the approximate foreign equivalent, the Mountain limestone 

 of Belgium and Britain: The collection of Mr. Ad. Piret at Tournai, acquired in 1888; and 

 all the important crinoid material collected by him for the next 20 years, including some 

 especially valuable specimens for the study of this group. A good series embracing most of 

 the known species from the British rocks in Waterford County, Ireland, and in Yorkshire, 

 England. 



