BIBLIOGRAPHY. 13 



To no one am I more indebted than to Prof. Charles Schuchert, of Yale University, whose 

 suggestions and comments, made in response to questions submitted to him, and also as the 

 result of examining the plates and the prehminary draft of the zoological discussion, have 

 been most helpful. 



From year to year material for study was brought in by various members of the United 

 States Geological Survey as opportunity offered, and large collections were made in the Cor- 

 dilleran area of the United States by Mr. S. Ward Loper, of the Wesleyan University museum. 

 I collected personally from various parts of the United States and Canada, England, and Wales, 

 being assisted in the Cordilleran area by Mr. F. B. Weeks and Mr. Lancaster D. Burling. 



During the course of the preparation of this monograph I have received from time to time 

 effective assistance from members of the United States Geological Survey, especially those 

 directly acting as my assistants. Wlien studying the Acrotretidse Dr. George H. Girty selected 

 material for illustration and also made preliminary notes on some of the species. Miss Elvira 

 Wood separated and classified the brachiopods collected in 1905-6, directed the preparation 

 of drawings, and, in 1906, revised the proof of the plates, which were printed at that time. 



Mr. Lancaster D. Burling, of the United States National Museum, revised, verified, and 

 tabulated the synonymy and localities and assisted in many ways in the final make-up of the 

 text of the volume from 1907 to 1912. 



At my request Mr. E. O. Ulrich, of the United States Geological Survey, carefully read the 

 zoological discussion and made notes that led me to make several modifications, especially in 

 relation to the protrematous genera. I have included in the text his observations on the 

 spondylium. 



To Mr. R. S. Bassler, of the United States National Museum, I am indebted for a number 

 of thin sections of the ' shells of Cambrian bracliiopods and a few Ordovician orthoids and for 

 notes on the sections. 



The drawings have been prepared mainly by Miss Frances Wieser, of the United States 

 Geological Survey. The plates are the evidence of her faitlrful work. 



HISTORICAL DATA. 



BIBLIOGRAPHY. 



The following bibliography includes the works referred to in this monograph, ° arranged 

 alphabetically by authors and chronologically under each author: 



Ami, H. M.: 



1887. The Ottawa Naturalist, vol. 1, No. 9, 1887 (Dec), pp. 121-126: Notes on, and the precise geological horizon 

 of, Siphonotreta scotica Davidson. 

 Bakrande, J. (see also de Veeneuil and Bareande): 



1848. Naturwissenschaftliche Abhandlungen, gesammelt und durch Subscription herausgegeben von Wilhelm 

 Haidinger, Bd. 2, Abth. 1, No. 5, 1848, pp. 153-256: Ueber die Brachiopoden der silurischen Schichten 

 vonBohmen. 4°. Wien. 

 1868a. II: Fauna silurienne des environs de Hof, en Bavifere, 1868 (Dec), pp. 31-110 (published with 1: Reap- 



parition du genre Arethusina Barrande.) 8°. Prague. 

 1868b. Neues Jahrbuch fiir Mineralogie, Geologie, und Palseontologie for 1868, pp. 641-696: Silurische Fauna 



aus der Umgebung von Hof in Bayern. 

 1879a. Systeme silurien du centre de la Boh^me, vol. 5, pt. 1, 1879, pp. 1-226, Pis. I-LXXI. 4». Prague. 

 1879b. Systeme silurien du centre de la Boheme, vol. 5, pt. 1, 1879, Pis. LXXII-CLIII. 4°. Prague. 

 Barrois, C: 



1882. Memoires de la Societe geologique du Nord, tome 2, Mem. 1, 1882: Becherches sur les terrains anciens des 

 Asturies et de la Galice (Espagne). 

 Bassler, R. S.: 



The lists of phyllopods cited under several of the localities on pages 161 to 291 were furnished to me by Mr. 

 Bassler from a manuscript copy of Ulrich and Bassler's memoir on the Phyllopoda, which is now in press. 

 Bebcher, C. E.: 



1891. American Journal of Science, 3d ser., vol. 41, 1891 (April), pp. 343-357: Development of the Brachiopoda. 



o Exceptions are: Albers, p. 434; Balsamo-Crivelli, p. 441; Baly, pp. 332 and 334; Clarke, p. 441; Iddingsand Weed, p, 417; Marshall, pp. 

 434 and 441; and Stose, p. 271. 



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