322 Remews — Geological Survey of Illinois. 



finally closed. These Eeports, second only in importance to those 

 of the State of New York, have very materially contributed to the 

 advancement of Geological Science on the North American Continent, 

 and they serve as a permanent memorial in honour of Prof. A. H. 

 Worthen, the State Geologist, by whom they have all, with the 

 exception of the closing volume, been edited. To a great extent 

 the present volume was also prepared under his superintendence, 

 but death removed him from his labours, whilst the work was going 

 through the press. The final editing was completed by Dr. J. 

 Lindahl, the successor of Prof. Worthen on the State Survey, and it 

 is very appropriate that a sketch of the life and scientific work of 

 the late Director should have been included in the contents of the 

 final volume. Dr. Lindahl has further contributed a General Index 

 to the entire series, which will prove of considerable assistance to 

 all palaeontologists and others who may require to refer to it. 



The present volume commences with a chapter on the Drift 

 Deposits of Illinois by Prof. Worthen. From this it appears that 

 they vary in thickness from 10 to 350 feet, and they often extend 

 below the present drainage level of the streams and rivers. The 

 Drift materials are thickest in the central portions of Illinois, they 

 thin out to the south of the State, and, with the exception of the 

 Loess, they all disappear before reaching the Ohio Eiver. The 

 lowest beds consist of stratified sands and clays filling up pre- 

 glacial valleys, over these a layer, 2 to 13 feet thick, of peaty soil 

 filled with plant remains, is usually present. This old soil is covered 

 by Boulder-clays, from 20 to 100 feet in thickness, and these again 

 are partially covered by modified drift and loess containing the 

 bones of Mastodon, Mammoth, Bos, Castoroides, etc. In some 

 places there appears to be a deposit of Boulder-clay material beneath 

 the peaty soil as well as overlying it. The preservation of this 

 soft peaty soil leads Prof. Worthen to the conclusion that the 

 Boulder-clay must have been produced by floating ice rather than 

 by glaciers. 



In a second chapter the same author gives the results of numerous 

 borings for coal and in search of natural gas and oil, but though 

 some of the borings have been carried to a depth of over 2300 feet, 

 penetrating nearly to the base of the stratified rocks in the region, 

 no economical results as regards gas and oil have been obtained. 



The second part of the volume is devoted to Palaeontology, and 

 the first section contains descriptions of fossil Invertebrates by 

 A. H. Worthen. Numerous species of Corals, Crinoids, Molluscs, etc., 

 for the most part from difi"erent divisions of the sub-Carboniferous, 

 are treated, but they do not seem of special importance. The 

 discovery of a new species of Ascocei-as, A. Southwelli, from the 

 Niagara Limestone, is of interest. 



In section ii. Messrs. Wachsmuth and Springer describe new 

 species of Crinoids and Blastoids from the Lower Carboniferous of 

 Le Grand, Iowa, and from the Niagara Group of West Tennessee. 

 Not infrequently the stems of these Crinoids are preserved intact, 

 and in almost all cases they taper distally to a fine point and give 



