PRELIMINARY STATEMENT OF THE PALEONTOLOGIC 

 RESULTS OF THE AREAL SURVEY OF THE OLEAN 

 QUADRANGLE 



BY JOHN M. CLARKE 



In the course of this work undertaken with the cooperation 

 of the U. S. geological survey during the season of 1900, opera- 

 tions were carried on mainly by Prof. L. 0. Glenn with the 

 assistance of Charles Butts. Mr Butts was specially con- 

 cerned in the collection of paleontologic data from all available 

 stratigraphic horizons and the careful study and determination 

 of material accumulated by him has led to a pretty clear under- 

 standing of the succession of the faunas in the district. It has 

 been well understood that the lower lands of the region w T ere 

 underlain by rocks which could be referred without question to 

 the upper layers of the Chemung formation but the strata cap- 

 ping the hills of the southern portion of the area have been 

 variously referred to the Devonic and in part to the lowest beds 

 of the Carbonic. The vagueness of this reference and the want 

 of any recognized line of division between accepted Devonic and 

 supposed Carbonic has been due partly to lack of requisite 

 study and partly to the gradual and undisturbed succession of 

 sedimentation. Between what has heretofore been supposed 

 to be Carbonic (without taking into account any more exact 

 denomination of the horizon) and the recognized Chemung 

 is a series of beds which has been usually termed Cats 

 kill and in part so represented on the geologic maps of the state. 

 One of the direct purposes of this work was to determine the 

 value of these beds over an interval where a passage from one 

 of the great paleozoic systems into another was clearly to be 

 looked for. That there is no Catskill sedimentation here in the 

 true meaning of the word, i. e. Catskill in the sense of implying 

 estuarine sedimentation with distinctive organisms of fresh or 

 brackish water habit such as occur in the typical section of 

 eastern New York, is made quite probable. In a general way 

 the section of sediments from north to south across this sheet 



