PREFACE. 



In the history of American paleontology the name of Gerard Troost 

 must always fill a conspicuous place. Doctor Troost was born at Bois- 

 le-Duc, Holland, on March 15, 1776.° His collegiate training was 

 received in the University of Leyden, where he was graduated as 

 doctor of medicine. He also received the degree of master of phar- 

 macy, and practiced that profession in his native country for six 

 years. 



In 1807 Doctor Troost went to Paris, where he continued his sci- 

 entific studies, and during his residence in that city he met and freely 

 associated with the leading scientific men of the time. Haiiy was his 

 teacher, and Humboldt and Werner were among his friends. 



Under the patronage of Louis Napoleon, King of Holland, Troost 

 traveled extensively in western Europe, and in 1809 was appointed a 

 member of a scientific commission to be sent to the island of Java; 

 but, owing to the disturbed political conditions of the time the expe- 

 dition was abandoned, and in 1810 he came to this country. He set- 

 tled in Philadelphia, where his social qualities as well as his scientific 

 attainments won for him early recognition from the scientific men of 

 that city. He became one of the founders and the first president of 

 the Philadelphia Academy of Sciences, retaining that office for five 

 years. While in Philadelphia Doctor Troost delivered courses of lec- 

 tures on mineralogy and chemistry, and also made a geological survey 

 of the environs of Philadelphia. 



In 1827 Doctor Troost moved to Tennessee, where he was shortly 

 after invited to accept the chair of geology and mineralogy in the 

 University of Nashville, a place which he held for the remainder 

 of his life. Later, the office of geologist of the State of Tennessee 

 was created and given to Doctor Troost. His researches within the 

 State gave an important impulse to the development of the natural 

 resources of Tennessee, and it was while traveling in connection with 

 his work that he made the collection of crinoids which form the basis 

 of this bulletin. 



" For the facts here given the writer is indebted to the excellent biographical .sketch 

 of Doctor Troost by Mr. L. C. Glenn (1905). 



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