1 PEOCEEDZffGS OF THE GEOLOGICAL SOCIETY. 



long depressed under the sea, whilst the ancient limestones of Illinois 

 bear no evidence of any superior deposit having covered them, and 

 exhibit only the results of long- continued atmospheric action. The 

 authors of the Report, indeed, hold that this part of the country has not 

 been under water since the deposition of the Upper Silurian rocks. 



Numerous details of great value for the comprehension of local 

 conditions are given in the special Reports on particular Counties 

 prepared by different members of the Survey; and an interesting 

 discourse on the origin of the Prairies, by Prof. Leo Lesquereux, 

 states the opinions of other authors on the subject, and gives his own 

 view of their formation by changes in the direction of the drainage 

 of the country, as illustrated especially by the now advancing trans- 

 formation of the Bay of Sandusky, 



The second volume is occupied by a series of Reports on the 

 Palgeontology of the district, in which Prof. Worthen has been aided 

 by Messrs. Newberry and Meek for the Vertebrates and Inverte- 

 brates respectively, whilst a new Batrachian from the Coal-measures 

 is described by Prof. Cope, and a number of new Polyzoa by Dr. 

 Prout. The fossil plants are figured and described by Prof. Lesque- 

 reux, and the numerous plates do great credit to the work of the 

 "Western Engraving Company of Chicago. 



Before proceeding to notice new works in special walks of our 

 science, I must in a few words advert to two books of a more general 

 and wide scope, in which we may feel almost a personal interest. 



It is a great satisfaction to one like myself, brought up from boy- 

 hood to appreciate the unwearied exertion and the logical reasoning 

 which have rendered famous the name of Lyell, to be able to an- 

 nounce the completion of the tenth edition of the ^ Principles of 

 Geology.' The first volume appeared last year ; and so much has 

 it been enriched by matter gathered together during the past thirteen 

 years, that all those students of nature who have enjoyed the multi- 

 farious additions to the earlier portion of Sir Charles's treatise, wiU 

 be impatient to see the second volume, which is not yet issued by 

 the publisher*. 



In the same year has been issued the new edition of ' Siluria,' on 

 which we may congratulate our veteran leader Sir Roderick Murchi- 

 son, not only that his domain appears to be constantly extending 

 into new regions, but that the book itself has been amplified and 

 revised with an amount of labour testifying to his unimpaired mental 

 and bodily vigour. All geologists wiU be aware that considerable 

 changes have been needed within the last half a dozen years in con- 

 sequence of the discoveries of Sir W. Logan in Canada, of the works 

 of Barrande in Bohemia, Harkness in Cumberland and Westmore- 

 land, of the determination of the New-Red- Sandstone reptiles by 

 Huxley, and, last though not least in the estimation of the outer 

 world, by reason of the facts promulgated concerning gold, which 

 have led to the modification of views put forth in the older editions. 

 And still, as before, all who are desirous of examining our own more 



*[The second volume has been pubHshed since the reading of this Address. — 

 Edit.] 



