August 15, 1902.] 



SCIENCE. 



259 



the summit of the Cai'boniferoiis column 

 and probably of Permian age. The city 

 itself is located mostly on the Conamaugh 

 formation or the old Barren Series of Rod- 

 gers, the central red beds of which crop 

 along all the railroads Avhich enter the city 

 and give no end of trouble from landslides, 

 slips and caves. These red beds enclose 

 one of the most interesting deposits of the 

 entire Carboniferous column, viz., the 

 Ames or Crinoidal limestone. It marks 

 the end of marine life in the Carboniferous 

 waters of the Appalachian field, and is a 

 most important ' key ' rock. Coming as it 

 does 300 feet below the Pittsburgh coal 

 bed, and at an equal interval above the 

 Upper Freeport seam, it has been traced 

 from central West Virginia around through 

 western Pennsylvania, across Ohio, and 

 back into southern West Virginia near 

 Huntington. 



Within easy access from Pittsburgh the 

 geologist may see all of the Carboniferous, 

 and on the crest of the great Chestnut 

 Eidge arch above Connellsville get a peep 

 deep down into the Devonian. 



This, however, has been given in the dia- 

 gram before you, which represents the 

 rocks under Pittsburgh as revealed in the 

 deepest oil boring ever made in America, 

 and, with one exception, the deepest in the 

 world. This record we owe to the intelli- 

 gent interest in pure science of Mr. W. J. 

 Young, of Pittsburgh, now at the head of 

 the great producing interests of the 

 Standard Oil Co. At an expense of many 

 thousands of dollars Mr. Young drilled 

 this well near West Elizabeth, Pa., to a 

 depth of 5,575 feet, and gave to Professor 

 Hallock, of Columbia University, the op- 

 portunity to make his important contribu- 

 tions to earth temperatures. This is but one 

 of numerous examples of encouragement to 

 pure science given by the officers and agents 

 of that much-abused organization. 



But interesting as are the stratified rocks 

 of the remote past in the Pittsburgh region, 

 the surface deposits tell for many a still 

 more attractive story. The clays, silts, 

 sands, gravels and cobbles which rest upon 

 the ancient river bottoms, and mantle up 

 the slopes to 300 feet above the present 

 streams, unfold a most interesting history. 

 They reveal a river during Tertiary time 

 flowing with its bed immediately under the 

 site of the Carnegie Institute, 200 feet 

 above the present streams, descending with 

 gentle fall (only one third the rate of the 

 present rivers), and at Beaver, instead of 

 turning southward down the Ohio, keeping 

 northward and joining the St. Lawrence 

 system in the region of Lake Erie. 



Then in Quaternary time, this north- 

 ward-flowing river was met by a great mass 

 of southward-moving ice and other glacial 

 debris which effectually impounded the 

 Allegheny and Monongahela drainage, and 

 caused their waters to intermingle across 

 the Bast Liberty valley, and finally to cut 

 a new pathway to the sea along what is 

 now the Ohio River. This great inland 

 lake is marked by a series of deposits of 

 clay, sand, boulders and other transported 

 materials upon all except steep surfaces up 

 to a little more than 1,000 feet above tide 

 over the entire basin of the two rivers. 

 Mr. Campbell, of the U. S. Geological Sur- 

 vey, has recognized the character of these 

 upland deposits as having been made in 

 a lake-like body of water, but has erro- 

 neously referred them to a local ice dam. 

 The one great dam which we know existed 

 just north from Beaver will explain all the 

 phenomena. 



The Loiuer Carboniferous of the Appala- 

 chian Basin: J. J. Stevenson. (Read 

 by title.) 

 In this paper a description is given of 



the several divisions of the Lower Car- 



