HELDERBERG DIVISION. 
331 
limestone along the brow of the hill and at the cement beds of Hasbrouck’s quarries* dip 
about eighty degrees west-northwest, and this dip continues nearly uniform along this line of 
upheave to the “ High rocks” above Kingston point (Vide PL 8, fig. 7). 
At Lawrence’s quarry, opposite Wilbur, at the southwest end of the limestone hill on the 
right bank of the Rondout, is a fine exposure of the different strata, and the Hudson slates 
are seen unconformahle, below the limestone (Vide PL 26, fig. 1). 
The following is an approximative section of the rocks at the south-southwest end of that 
hill : 
1 . 
2 . 
3. 
4. 
5. 
6 . 
7. 
8 . 
9. 
10 . 
Fossiliferous limestone like the “ middle limestone of Becraft’s mountain” (d) 
Fossiliferous limestone, different from the above, and containing hornstone (c) 
Compact dark grey limestone, (contains encrinal spines and the pentamerus) _. 
Clouded striped limestone__ 
Cement rock (grey)- 
Compact black limestone_ 
Cement rock (grey), four strata___ 
Black coralline limestone (various radiaria, cyathophillia, catenipora, etc.)_ 
Cement rock (grey to black)___ 
Limestone, dark colored, impure and fossiliferous_ 
60 feet. 
50 “ 
34 “ 
20 “ 
2 « 
1 “ 
12 “ 
8 « 
8 « 
8 “ 
Thickness of the limestones and cements_ 203 feet. 
11. Hudson slates and grits, thickness unknown [a). 
At the extreme southwest end of the hill, the strata are much deranged and bent; but a 
little farther east, at the quarries, and along the face of the cliff, they are finely exposed, 
dipping at a moderate angle to the east-southeast. 
The limestones of the Helderberg division overlie the slates of the Champlain division un- 
comformably, at Becraft’s mountain, near the Hudson. The unconformability, faults, and 
overturning of some strata are represented on Plate 24, figs. 4, 5, 6 ; and of Mount Bob, PL 
There is an anticlinal axis along the broken ridge between the Esopus creek and the 
Rondout. The rocks on the northwest of this axis dip to the west-northwest at a small angle, 
conformable to the general dip of the rocks which overlie them on the northwest side of the 
valley, and which do not appear to have been much disturbed by the upheaving action that 
has dislocated and upturned all the rocks east and south of this valley. On the southeast of 
this axis, the strata are broken and upheaved, dip to the south-southeast at angles from twenty 
to eighty degrees, and present successive mural escarpments (Vide PL 8, fig. 9). There are 
several anticlinal lines, and lines of fault parallel and subordinate to the main axis. One of 
them passes through two small lakes in Marbletown (Vide PL 8, fig. 10; and PL 26, figs. 2, 
* Mr. Hasbrouck has three quarries leased out on Pine mountain, between Rondout and Kingston point. One of them, six 
hundred and fifty feet in length, is leased for two hundred and fifty dollars per annum, and yields about forty tons of cement rock 
per diem, which is sent to Newark, New-Jersey, to be burned. 
42* 
