266 Joseph Barrell. 



and from personal observation. He concludes that ''In 

 the anthracite region, more surely in the southeastern 

 and eastern portions, the whole formation [which is 

 about 3,000 feet thick], from top to bottom, was a sub- 

 aerial [delta] deposit laid down under a semiarid cli- 

 mate." The nearest approach to-day to a similar area 

 is that of the highly arid Punjab region near the base 

 of the Himalayas, and of the lower plains of the Indus 

 River. "These comparisons, while not intended to con- 

 vey the idea that the Appalachians were ever of Hima- 

 layan magnitude, are suggestive of a more massive 

 range of mountains and a wider land area to the east- 

 ward of the Pennsylvanian geosynciine than is custom- 

 arily thought of as existing in Upper Devonian and 

 Carboniferous times." 



Having seen much of the Carboniferous of eastern 

 Pennsylvania, Barrell had asked himself, ''To what ex- 

 tent have the tectonic movements and climatic variations 

 caused the great contrasts seen here in the Lower and 

 Upper Carboniferous formations!" To solve this prob- 

 lem, he took up in detail the principles that have to do 

 with the relations between modern climate and terres- 

 trial deposits, and published his conclusions in "Rela- 

 tions between Climate and Terrestrial Deposits." He 

 writes: "The environment of the lands may be classi- 

 fied into three fundamental and independent factors — 

 the relations to the surrounding seas, the topography 

 which forms their surfaces, and the climates which en- 

 velope them; each of major importance in controlling 

 the character of the lands." Fundamental are the 

 relations of continental fluviatile deposits to the cli- 

 mates, and they may be successfully used in determin- 

 ing those of the geologic past. "This is exclusive of 

 the significance of salt and gypsum deposits on the one 

 hand or of glacial deposits on the other, which are of 

 course universally recognized, but these are the marks 

 of climatic extremes." 



The first part of the paper under review has to do 

 with the relations of sediments to regions of erosion. 

 It deals with the relation of physiography to erosion 

 and the consequent supply of waste as sediments to 

 the formations. Then he takes up the relations of sedi- 

 ments to regions of deposition, and finally the relations 

 of climate to fluviatile transportation. These parts 



