THE SECTION AT SCHOHARIE, N. V. 371 



them weather light gray. The shales are hard but weather 

 readily. As a whole the rocks wear away easily so that the 

 place of the Delthyris is marked by a slope between cliffs made 

 by the Lower and the Upper Pentamerus, This slope on the 

 east side of the valley is long and gentle so as to be cultivated 

 and there are few satisfactoiy exposures ; but the slope is com- 

 paratively steep on the west side and an almost continuous ex- 

 posure is found on the schoolhouse hill in a little waterway. 

 Imperfect exposures only were found on West mountain near 

 Murphy's, though there one finds the best exhibition of the 

 uppermost beds. The most extensive exposure is on the west 

 side of Schoharie river below Davis's dam, where one sees all 

 the beds, except the topmost, as they descend to the river ; 

 when the water is low, a horizontal space of 25 to lOO feet is 

 bare. 



The lower portion for about fifteen feet is silicious and con- 

 tains much chert. It is shown on the schoolhouse hill where it 

 can be followed for a long distance ; but a proper understanding 

 of the structure of this portion can be gained only at the Davis 

 dam locality, where the broad surface shows the interlacing of 

 the cherty masses. The fossils in this part are numerous and 

 beautifully preserved ; they are all silicified but cannot be re- 

 moved except by weathering. The rock is refractory and is 

 apt to break at the wrong place for the collector. The highest 

 beds are soft calcareous shales best shown on West mountain at 

 the Murphy place, where for a hundred feet or more they have 

 rotted away leaving a recess under the Scutella- Pentamerus cliff 



The Delthyris is fossiliferous throughout and in many of the 

 beds perfect specimens are the ordinary condition. Owing to 

 the readiness with which the softer beds weather, specimens are 

 set free in great number. Some forms are present throughout. 

 At Davis' dam Spirifcr inacroplciira makes its appearance in 

 the cherty beds and persists to the top of the series. It was 

 not found in the highest shales at the Murphy locality. Atry- 

 pina imbricata and Coelospira concava are rare in the upper 

 shales though abundant in the beds below. The most char- 

 acteristic forms occurring throughout the Delthyris are Zapli- 



