36 



SECTION V. 



Descriptions of Lower Silurian Sponges, E. O. ULRICH and 

 OLIVER EVERETT 253-282 



SECTION VI. 



Palaeozoic Bryozoa, E. 0. ULRICH , 283-678 



Index to Part 1 689-691 



Index to Part II, Sections I, II 693-699 



Index to Part II, Sections III, IV and V... 701-706 



Index to Part II, Section VI 707-727 



Table of Contents to Part II, Section VI 728 



Plates I-LXXVIII and explanations. 



APPENDIX. 



The Private Life and Scientific Works of PROF. AMOS HENRY 

 WOKTHEN, by N. W. Bliss and C. A. White, with a portrait 

 of Prof. Worthen, by Jacques Reich 3-37 



General Index to Geological Survey of Illinois, A. H. WOR- 

 THEN, Director, Vols. I-VIII, by Josua Lindahl 39-151 



Approximate Geological Map of Illinois. 



The foregoing list comprises all the publications of Professor 

 Worthen that have come to the knowledge of the writer, and 

 it is believed to be nearly or quite complete. It is proper to 

 say that nearly or quite all the matter contained in the publi- 

 cations mentioned in that list, exclusive of the eight large vol- 

 umes of Survey reports, is also contained in those volumes in a 

 completed form. That is, those publications consist of material 

 which was printed in advance of the reports, or of tha.t which 

 has been abstracted from those volumes after their publication. 



The eight large volumes and accompanying maps therefore 

 represent fairly the results of Professor Worthen 's life work. 

 It is impracticable to present an extended analysis of that 

 work on this occasion, but the following brief summary will 

 serve to give an indication of its magnitude. 



This great work embraces the geology, both structural and 

 economic, and the palaeontology of Illinois. In the geological 

 division was accomplished the mapping, upon one comprehensive 

 sheet and various smaller ones, the nearly 56,000 square 

 miles which are embraced within the boundaries of that State, 



