Geology and Natural History. 267 



cal Survey. Under present conditions, accuracy and complete- 

 ness in topographic and geologic work have reached a much 

 higher level than was possible under the conditions controlling 

 the earlier state surveys. 



The present volume will doubtless be welcomed by the people 

 of Pennsylvania as well as by students of geology in general, 

 because it contains within a reasonable compass a discussion of 

 the salient features of the geology of the state. By means of 

 this General Review it is possible now to get a clear conception of 

 Pennsylvania geology, stratigraphic and physiographic, as well 

 as economic, and including recent discoveries, without reading 

 through a mass of detailed and technical description. The gen- 

 eral geologic report has been largely written by R. W. Stone, the 

 pre-Pennsylvanian stratigraphy by Charles Butts, the petroleum 

 and gas report by M. J. Munn. h. e. g. 



3. Virginia Geological Survey; Thomas L. Watson, Direc- 

 tor. Bulletin No. II-A ; The Cement Resources of Virginia, 

 West of the Blue Ridge, by Ray S. Bassler, with an Introduc- 

 tory chapter on the Materials and Manufacture of Hydraulic 

 Cements, by Edwin C. Eckel. Pp. xii, 309, 30 plates, 30 figures. 

 Charlottesville, 1909. — The development of the cement industry 

 in Virginia justifies the publication of the present report, which, 

 however, is more than an economic paper, and includes a valuable 

 report (pp. 136-185), chiefly stratigraphic, on the geology of 

 western Virginia, a region which has heretofore been inadequately 

 studied. h. e. g. 



4. Illinois State Geological Survey ; H. Foster Bain, Direc- 

 tor. Bulletin 11 ; Physical Features of the Des Plaines Valley, 

 by James Walter Goldthwait. Pp. x, 103, 9 plates and 21 

 figures. Urbana, 1909. — Attention has previously been called to 

 the admirable series of Educational Bulletins dealing with the 

 geology of the state of Illinois, planned by the Illinois Geological 

 Survey. This present bulletin is fully up to the standard of the 

 others, and amply justifies the labor expended. Too little atten- 

 tion has been paid by state and national surveys to the needs of 

 teachers and general readers ; and it is hoped that this series, 

 dealing in a more or less untechnical way with interesting type 

 localities, will encourage other organizations to undertake a similar 

 work. H. E. G. 



5. Geology and Water Resources of the Northern Portion of 

 the Black Hills and Adjoining Regions in South Dakota and 



Wyoming ; by N. H. Darton. Professional Paper, U. 8. G. S., 

 No. 65, 1909. Pp. 105, 24 plates, 15 figures. — Several previous 

 papers and reports by Mr. Darton, dealing with the Black Hills 

 and the surrounding region, have presented the geology of this 

 interesting area in an exceptionally attractive manner. These 

 papers of Darton's taken in connection with the reports by 

 Professor Jaggar and Professor Irving, and the earlier report of 

 Xewton and Jenney, constitute a body of geologic literature 

 available for few areas in the United States. 



