524 Butts — Geologic Section of Blair and 



nings formation of Maryland, except that the Woodmont 

 extends down to the Bnrket black shale member, regarded 

 by the Maryland Survey as Genesee. The Brallier is 

 well exposed and can be most conveniently seen along the 

 Pennsylvania Railroad west of Altoona and just east of 

 Huntingdon. The Harrell shale is perfectly distinct 

 lithologically from the Brallier, as shown by the descrip- 

 tions of the section. In the Broad Top Mountain syncline 

 in Huntingdon County the Harrell is about 250 feet 

 thick and consists of soft, dove-colored fissile shale 

 and interbedded layers of black fissile shale. In Blair 

 County, to the west, however, the black shale is all in the 

 bottom and is about 75 feet thick, the soft, dove-colored, 

 highly fissile (paper) shale, about 200 feet thick, being 

 free of black shale and forming the upper part of the 

 Harrell. The name is taken from Harrell, a station on 

 the Petersburg branch of the Pennsylvania Railroad, 

 about midway between Hollidaysburg and Williamsburg 

 where the dove-colored shale is well displayed. This 

 shale is also well shown in a cut of the Pennsylvania 

 Railroad in the western outskirts of Altoona and in the 

 brick yard at Eldorado, a few miles south of Altoona. 



The black shale member of the Harrell is named from 

 Burket, a suburb of Altoona. The Burket member is 

 well exposed in and about Altoona, at several places 

 southwest of Altoona for 20 miles, and along the Penn- 

 sylvania Railroad between Altoona and Bellwood. As 

 already stated, this shale has been regarded as Genesee, 

 but it carries no distinctively Genesee fossils; on the 

 other hand, it and the overlying part of the Harrell gen- 

 erally contain a good representation of the Naples fauna, 

 found at the base of the Portage in western New York. 

 The Burket is, therefore, believed to be basal Portage 

 rather than Genesee. 



Just below the Harrell shale there is, in places at least, 

 a limestone about a foot thick, from which were obtained 

 Chonetes aurora and a Martinia like one of those of the 

 McKenzie River region of Canada, which are there also 

 associated with the same Chonetes. As Chonetes aurora 

 is a characteristic fossil of the Tully limestone of New 

 York, to which it appears to be confined, the thin lime- 

 stone here is probably the feather edge of the Tully 

 extending in an embayment into this part of Pennsylva- 

 nia. If so the limestone really belongs in the Upper 



