THESAURUS SILURICUS. 



THE 



FLORA AND FAUNA 



OF THE 



SILURIAN PERIOD. 



WITH 





ADDENDA 



(FROM RECENT ACQUISITIONS). 



BY 



JOHN J. BIGSBY, M.D., E.G.S., 



FORMERLY BRITISH SECRETARY, CANADIAN BOUNDARY COMMISSION; MEMB. AMER. PHILOS. SOC. PHILAD. ; 



CORRESPONDING MEMB. ACADEMIES OF NAT. SCIENCES, PHILAD. AND ST. LOUIS ; OF THE 



LYCEUM, NEW YORK. HONOR. MEMB. ROYAL BOHEMIAN MUSEUM, PRAGUE. 



" The boldest and happiest generalizations must depend on details." Dean CONYBEARK. 



LONDON: 

 PUBLISHED BY JOHN VAN VOORST, PATERNOSTER ROW. 



MDCCCLXVIIL 



