138 PRIMORDIAL—WAPPINGER LIMESTONES. 
east of this strip may form the western margin of the 
Calciferous strata. In this case the small quarry in the 
field of W. 8. Johnston, at the southeastern portion of 
the district (H), would be near the eastern edge of the 
Potsdam. This view is strengthened by the fact that 
lines of ponds and springs exist conspicuously along the 
base of this long eastern hill, indicating a possible break 
or slip between strata along this line. But as fossils 
have not yet been found in the last-mentioned hill, 
nothing more positive can be asserted in this connection 
-at present. 
A brief description may now be given of the paleonto- 
logical features of these strata. 
In the fossiliferous hill above described (A), organic 
remains are found chiefly on the eastern side near the 
summit in the southern half, though not in the odlytic 
portion. They occur both in the solid fissile limestone, 
and in thin layers of shale associated with it. The fos- 
sils are present in considerable numbers but so much 
scattered through the rock that large masses must be 
broken up to obtain a few organisms. 
IT have also found a few specimens of Lingulepis in 
the extension of the western fork of this hill in the 
second and third fields beyond, where it becomes a blue 
calcareous shale (KE). 
No fossils have yet appeared south of Mr. Smiley’s 
property, that is, south of the fourth field from the 
driving-park, except some Stromatoporoid forms which 
are not infrequent throughout the Potsdam strata. 
From these localities I have already collected over five 
hundred fossils ; some of these are in a perfect state of 
perservation, while many are in a very imperfect and 
fragmentary condition. There is no doubt whatever as 
to the presence among them of several well-known and 
well-marked Potsdam fossils, while the whole group ap- 
pears to belong to that geological horizon. Since, in my 
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