12 PREFACE. 



For a long time there has been a wide-spread desire among 

 certain classes of citizens for a more concise account of the 

 organic remains of the State, especially in the light of the fact 

 that fossils have such a distinct economic importance in 

 determining the age of rocks, and hence serve as trusty guides 

 in the further development of our mineral wealth. In the 

 attempt to satisfy properly the demands arising in connection 

 with a work of this character, it is the intention to present, as 

 briefly as possible: (1) an index to the fossils of the State, 

 through means of which the forms now known to occur within 

 the limits of the region under consideration can be recognized 

 readily, without recourse to great libraries ; (2) a bibliography 

 of Missouri Paleontology, bringing together all that has been 

 written on the subject, now so widely scattered and practically 

 inaccessible ; (3) a summary of what has been done up to the 

 present time in this branch of science, in so far as it pertains 

 to the State of Missouri; and (4) an introduction to more 

 comprehensive faunal studies, tending toward a solution of 

 stratigraphical problems at present more or less obscure. 



The material upon which the report is based has been 

 derived from various sources. The greater part of the spe- 

 cies illustrating the fossil faunas of the region has been col- 

 lected by different members of the Geological Survey of Mis- 

 souri. Supplementary to this a number of local cabinets in 

 the State have furnished iinportant series of particular groups. 

 Another fertile field for valuable Missouri specimens was the 

 many private collections belonging to persons residing outside 

 of the State, and to which free access was generously given 

 at all times. During the many years fossils have been col- 

 lected in Missouri a considerable number of forms have found 

 their way into the cabinets of various colleges and public 

 museums. Altogether, these collections furnished an amount 

 of reliable material that could not have been otherwise ob- 

 tained in years ot special work. 



In the present memoir, every endeavor has been made to 

 deal only with the species which have passed under personal 

 observation. In this way, secondarily acquired information 



