Jan., U)l/j The Future For Gcoolgists 87 



maps of sea and land, rivers and mountains, shorelines, islands, 

 straits and bays for every horizon over large areas; but if we 

 knew all the facts now recorded in the rocks of North America 

 we might be able to make a map for each of many horizons, 

 which would bo of profound significance and interest to the 

 paleontologist, the biologist, the economic geologist and the 

 geographer. 



Many paleogeographic maps have recently been made. 

 One set of about fifty by Charles Schuchert, of Yale, is a marvel 

 of what the paleogeographer can do. The series of final, 

 correct maps of a continent can not possibly be made until all 

 the continent has been mapped areally, and all correlations 

 of strata and unconformities have been established. 



All stratigraphic geologists are interested in making as 

 complete a columnar, stratigraphic section as possible. Mani- 

 festly such sections in separate localities cannot be alike, 

 unless the localities had the same conditions at the same 

 interval throughout all of geologic time. The correlation of 

 all sections one with another is a step in the making of the 

 paleogeographic maps, and in the interpretation of the strati- 

 graphy of a continent. Such correlation is done on the basis of 

 rock character and fossils. Let me quote a few lines from 

 Schuchert, in Pirsson and Schuchert's Text Book in Geology, 

 page 450, which may contribute to the problems, both of uncon- 

 formities and the making of the column. "These breaks are 

 known to be many, but they are far greater in number, and their 

 time durations, although admittedly very variable, are far 

 longer than is usually believed to be the case. The geologic 

 column will probably never be completed on the basis of the 

 recoverable physical and organic evidence, but it will grow into 

 greater perfection for a long time, through the discovery of 

 formation after formation along the lines (levels) of these 

 breaks. " 



4. The Paleontologic record in the rocks is largely yet to be 

 deciphered. At present every paleontologist recognizes great 

 breaks in the biologic succession. So numerous and great 

 are these gaps that the theory of evolution of later from earlier 

 forms cannot yet be considered a principle or law. Not until 

 a column is completed, and that too of fossiliferous strata, can 

 we know just what has been the succession of forms. The 

 paleontologist must go on collecting as the study of areal 



