INTRODUCTION. 5 



During the lifetime of Prof. Worthen^ the eminent Director of the 

 Illinois Geological Survey, and afterwards under the administration of his 

 accomplished successor, Dr. Josua Lindahl, we enjoyed the privilege of 

 unrestricted facilities in the use of the type and other specimens in the 

 State Museum of Natural History at Springfield. The private collection 

 of Worthen, containing a large number of the types of the earlier species 

 described in Hall's Iowa Reports, was packed up and inaccessible while he 

 held the position of State Geologist ; but after his death, when the col- 

 lection was acquired by the State of Illinois and incorporated in the State 

 Museum, w^e were permitted through the courtesy of Dr. Lindahl to 

 examine it, and were given full use of the valuable type specimens. As 

 a mark of our personal esteem, and in justice to the memory of this 

 pioneer collector and geologist, we have inserted the name of Worthen in 

 the notation of such of his type specimens as are now in the State Collection. 

 These types are of great value, as they are the only types of the early Bur- 

 lington and Keokuk species still in existence, so far as we know, with the 

 exception of a few in the Shumard collection. We have been unable to 

 obtain any information as to the types of Owen and Shumard's descriptions 

 in the Report for Iowa, Wisconsin, and Minnesota, in 1852, — the first Sub- 

 carboniferous Crinoids described from the West. A considerable part of the 

 collections made during the first Iowa Geological Survey are said to have 

 been destroyed by fire, either at Burlington or Keokuk, and it is supposed 

 that a number of type specimens were lost in this way. McChesney's types 

 were all lost in the great Chicago fire. 



The collections in the Canada Survey Museum at Ottawa, containing 

 the types of all of E. Billings's Lower Silurian species, and the later ones of 

 Whiteaves, have been freely open to us under the authority of Sir Alfred 

 Selwyn, and through the unremitting courtesy of Prof. J. F. Whiteaves. 



Through the attention of Dr. C. A. White and Prof. C. D. Walcott, we 

 obtained the use of the types of some of Meek's descriptions in the National 

 Museum at Washington. 



Prof. S. H. Williams of Ithaca, New York, had the goodness to furnish 

 us for examination the types of species described by him, from the Museum 

 of Cornell University, and some of the types from the Colonel Jewett 

 collection. 



Through Prof A. H. Winchell we had the use of the specimens in the 

 collection made by Dr. White, now in the University Museum at Ann Arbor, 

 containing the types of a number of well known Subcarboniferous species. 



