338 AMADEUS W. GRABAU 



year, but unfortunately not yet published. I quote from the 



manuscript: 



The upper 4J to 5 inches of the Prout has a peculiar character in that it is 

 full of pyrites, is irregularly bedded, and contains much glauconite. Black 

 shale specks and fish teeth are found in the upper half-inch. This upper part 

 of the limestone suggests a weathered and reworked portion very different 

 from the lower part, which is also dolomitized. Some doubtful limestone 

 pebbles have been found at the contact line in the base of the Huron shale, 

 but they are not sufficient in number to be of much value. Altogether, the 

 evidence is inconclusive, but it is not against the assumption of a disconformity 

 [between the Prout and the Huron] 



The abrupt contact and the absence of intergrading are further 

 indications of a pronounced change in sedimentation with a long 

 time interval between the two formations. A comparison of the 

 fauna of the Prout with that of the Traverse group of Michigan, 

 gone into at some length in my report, shows the former to corre- 

 spond to the lower Traverse of Michigan, i.e., to the beds below 

 the Alpena limestone. I quote again from my manuscript report: 



This means that the upper beds were never deposited or that they were 

 removed by erosion prior to the deposition of the black shale, for no one 

 would consider the black shale in any way contemporaneous with the upper 

 Traverse beds of Michigan. Thus an unquestioned time interval is indicated, 

 and since we find elsewhere the black shale disconformable upon the Traverse or 

 other Mid-Devonic beds, we need not hesitate to assume the same relation for 



northern Ohio Compared with the sections in northwestern Ohio and 



in Canada, the evidence becomes quite conclusive that between the Prout and 

 the Huron there is an unrecorded time interval. 



Quite recently Dr. Stauffer 1 has returned to a discussion of the 

 correlation of the Prout formation on the basis of its fossils, which 

 he listed in an earlier publication. 2 He comes to the conclusion 

 that the Prout limestone represents the Encrinal limestone of 

 Eighteen Mile Creek, 3 and the shales below it, the lower Hamilton 

 shales of western New York. 4 



1 C. R. Stauffer, "The Relationships of the Olentangy Shale and Associated 

 Devonian Deposits of Northern Ohio," Jour. Geol., XXIV, No. 5 (July-August, 1916), 

 pp. 476-87. 



2 Geol. Surv. Ohio. Bull. No. 10, 4th Series, 1909. 



3 1 have proposed the name Morse Creek limestone for this Encrinal of western 

 New York at the meeting of the Geological Society of America, December, 1914, 

 and in the report on The Devonic Formations of Michigan above referred to. It is an 

 older limestone than the Encrinal or Tichenor of central New York. See Bull. G. S. A ., 

 XXVI (1915), 113. 



4 Now designated the Wanakah shales by me. 



