498 [May 16, 
Glaypole.] 
And of the variegated shale he says (p. 97) : 
“Tt consists of shales and calcareous slate of a light green and drab 
color, intermixing and alternating with the red shale at its lower part. 
“Thus we have at the top of the series, green, then red under it, green, 
red, bluish, green and yellow, this latter by exposure to the air; then 
green and red layers with a little white and greenish sandstone, being 
several repetitions of the first two, and finally red shale as the lowest vis- 
ible mass.”’ 
No better description can here be given of these two shales as they 
occur in Perry county. 
The thickness of the separate beds is not given in Vanuxem’s Report, 
but the total mass varies from 700 to 1000 feet. In Perry county the two 
lower masses—the red and variegated shales—measure 1400 feet, making 
the whole group, as usual, much thicker in Pennsylvania than in New 
York. 
Again (p. 97.), ‘‘In several localities the red shale shows numerous 
green spots, varying from one inch or less to several inches in diameter. 
“The red shale presents a thickness of from one to nearly 500 feet, yet 
nowhere has a fossil been discovered in it, or a pebble or anything ex- 
traneous, excepting a few thin layers of sandstone.” 
Similar green spots occur in the red shale in Perry county (near 
Wagoner’s mill, for instance). The great scarcity of fossils is also re- 
markable, though these are not totally absent in Pennsylvania as will be 
mentioned farther on. 
Advancing one step more Jet us compare the third division in Perry 
county with the similarly situated beds in New York. Here again we 
find the description of Vanuxem applicable to a great extent. He says 
(p. 99): 
“The great mass of the deposit consists of rather soft, yellowish or drab 
and brownish colored shale and slate, both argillaceous and calcareous.” 
It contains ‘‘ argillaceous and calcarcous slates, and more compact masses, 
which are hard.’’ So in Perry county, though seldom exposed, this is the 
nature of the mass. 
But one very important difference in these gray marls at the two places 
must be mentioned. No trace exists in this part of Pennsylvania of those 
concretions of gypsum which characterize the upper part of the Onon- 
daga in New York, and which, together with its brine springs, render it 
the most valuable stratum in the State. These gray shales contain no 
valuable mineral, except the lime which enters largely into their composi- 
tion. Such deposits as the gypsum and salt in New York rarely extend 
over very great tracts of country. Their absence in Perry county is not 
an objection sufficient to invalidate the argument. Indeed, the gypsum 
is not present over all the Onondagan outcrop in New York. Professor 
Hall says (Geol. of 4th District, p. 126), ‘‘ There is a considerable space in 
the western part of Monroe county where no beds of gypsum are known.”’ 
