xiv PREFACE. 



tion ; to Mr. G. F. Matthew, of St. John, N. B., for the use of fossils of the St. 

 John group, and for valuable information concerning them ; to Hon. A. R. 

 C. Selwyn, Director, and to Mr. J. P. Whiteaves, Palaeontologist, for the use 

 of many typical specimens from the Museum of the Geological Survey of 

 Canada. Also to Mr. W. R. Billings, of the Department of Public Works, 

 Ottawa, Canada, and Mr. H. M. Ami, of the Geological Survey. 



From Mr. Thomas A. Greene, of Milwaukee, Wisconsin, I have received 

 most important material from the Niagara group of Wisconsin ; from Dr. Josda 

 LiNDAHL, Curator, and from the Trustees of the Illinois Museum of Natural 

 History, the free use of its collections ; from Prof C. L. Herrick, of Chicago, 

 the use of his typical collection of the Waverly group ; from Prof. James M. 

 Safford, of Nashville, Tenn., interesting material from his collections which 

 have been utilized in the illustration of the Orthidm. To Prof J. S. Newberry, 

 I am indebted for the free use of his very interesting collections, especially of 

 the Carboniferous fossils ; to Prof. Edward Orton, for his liberality in permit- 

 ting the free access to the collections of the Geological Survey of State of Ohio ; 

 to Prof G. C. Broadhead, of the University of Missouri, for the use of many in- 

 teresting forms of Carboniferous fossils ; to Rev. John Bennett, of Kansas City, 

 for the use of very interesting Coal Measure fossils, especially of the genera 

 Derbya and Enteletes ; to Prof. Samuel Calvin, of the University of Iowa, for 

 his liberal aid toward the illustration of the Silurian and Devonian Brachiopoda 

 of Iowa ; to W. C. Egan, of Chicago, for the use of some interesting forms of 

 Carboniferous fossils, and to Dr. C. Rominger for his liberal and intelligent con- 

 tributions to our knowledge and means of illustration of the Brachiopoda, an 

 obligation beginning as far back as 1863. 



From the American Museum of Natural History, through Prof. R. P. 

 Whitfield, specimens representing many genera and the types of many species 

 have been received ; from Prof. J. P. Lesley, State Geologist of Pennsylvania, 

 a series of inarticulate Brachiopods from that State; from Mr. Charles D. 

 Walcott the use of specimens and information concerning the same; from Prof. 

 James R. Eaton, of William Jewell College, Missouri, during many years, the 

 use of specimens and for much intelligent information ; from Rev. H. Hebzeb, the 



