SIXTH REPORT OF THE DIRECTOR I909 1 59 



Ellenville (O. & W.) Railway. These are wholly different in 

 appearance from the silicified shells of the Oriskany, Port Ewen 

 or Kalkberg- limestones and are readily distinguished. They 

 come from essentially shaly layers, are very delicate, neither 

 thickened, coarsened nor iron-stained but often semitranslucent 

 blue with the finest edges and markings sharply preserved. 

 The transition to< the Becraft and thence to the Port Ewen is 

 completely revealed, with excellent collecting opportunities. At 

 10, the west side of the same quarry, it appears impossible to 

 draw the Becraft-Port Ewen contact at a bedding-plane. The 

 two rocks are perfectly continuous, only the change of fossils 

 and the appearance of chert nodules marking the inception of 

 the Port Ewen. This is unusual ; a distinct bedding-plane 

 separates them at Rondout, Alsen and Catskill. 



From 10 a red barn is seen to the south, under the west base 

 of the hill. Mr Cole states that beds with many Homalo- 

 notus vanuxemi, supposedly Oriskany or perhaps upper 

 Port Ewen, occur from this barn southward, having a low west- 

 erly dip. 



Returning along the highway, another big cutting at n 

 shows the same fossiliferous New Scotland shales as at 9, and 

 these beds are being excavated again at 12, here quite vertical 

 to beyond vertical at the top. No attempt has been made to 

 discriminate the Kalkberg limestone in the field or on the map, 

 from the underlying Coeymans. 



The offset between the two halves of the hill is plainly evi- 

 dent. Only the narrow highway separates outcrops as discord- 

 ant as Oriskany and New Scotland, or Port Ewen and Coey- 

 mans, and this highway is seen to lie in an oblique hollow across 

 the hill having every earmark of a fault valley. Standing on the 

 north of the road, say at 6, the fault plane is felt to be the hill 

 slope on which one stands, dipping at a low angle to the west- 

 ward and a steeper angle to the southward. The fault block 

 is like the decapitated crest of this hill, slid westward and 

 slightly downward for the space of two or three hundred feet 

 upon the yielding surface of the Esopus shale (which makes 

 the next ridge to the west beyond the railway), just as at Ron- 

 dout. Of course, as a matter of fact, the slip took place under 

 much overlying rock and the present forms are erosional. The 

 movement was a true overthrust, not a landslide. One is 

 tempted to inquire whether this is not a piece of the identical fault 



