Starting on the trail, you will observe some of the formations on the rock walls. While walking down the stairs, you are passing through an old road cut. Originally, the Indian Ladder Road (constructed in 1828) went to the top of the escarpment where the trail now descends. The old road comes across the flats from Albany, up the cliff, and thence westward towards the Schoharie Valley.

The rock formation on the side of the stairway is Coeymans limestone. Look carefully and you will see fossilized remains of small sea creatures. Note the thickness of the layers of the Coeymans limestone. These layers are generally much thicker than those found in the Malius formation:

The path now runs along the Malius formation. It is thin-bedded, dark blue limestone which is less resistant than the Coeymans. The layers are especially thin in the lower part of the formation, with alternating light and dark beds.

At the top of the formation, between the Malius and Coeymans, is found a two to three feet thick layer of waterlime (Malius waterlime) which has been quarried and used in making Potland cement. Being very soft, it is readily removed by natural agents and forms the ledge throughout the part known as "Upper Bear Path."

At the bottom of the Manlius formation is a three to four feet thick, finely bedded lime murdock known as Rundout waterlime. This was named after the extensive quarries and cement mines in the vicinity of Rondout. It was mined for the manufacturing of natural or Rosendale cement. Because it is less resistant than the Manlius formation, it has also worm back to form the ledge on which you are standing, known as the "Lower Bear Path" or "Indian Ladder Trail."

Here you can see the characteristic cracks and vertical joints in the limestone. Fissures develop and become larger as the limestone is dissolved by the rain water.

Rain absorbs carbon dioxide, as it passes through the atmosphere and decaying organic matter in the soil, and becomes less acidic. This enables the ground water to slowly dissolve the limestone. You can obtain a similar reaction by placing a small piece of limestone in vinegar (a weak acid) and observing the results.

The large amounts of limestone in John Boyd Thacher State Park have certain associated natural phenomena. The solubility of the limestone explains the occurrence of disappearing streams, underground streams, caves and sinkholes.

Underground streams from as surface water seeps into the joints of limestone and eventually dissolve passages through the rock. The underground passages then enlarge, with time, to form the numerous caves in this region. Most caves in the region are still being formed. They are quite small and still have water running in them.

In a limestone region such as this underground solutions have caused cave-ins of the surface forming depressions of various sizes called "sinkholes." Such sinkholes are known as Karst Phenomina from their occurrence in the Karst region of the Dalmatian Alps.

Thompson's Lake, two miles west of the park, is such a sinkhole among other smaller ones nearby. The lake has no surface outlet, draining through a small cave at the southern end.

Outlet Creek, at one time, was much larger than it is now. At present, drainage in this region is primarily underground. Consequently, Outlet Creek is quite small.

Together with Minelot Creek, Outlet Creek carved out the large embayment (formation of bay) in the escarpment known as Indian Ladder Gulf. At the conclusion of the walk, you will not that the trail has followed the edge of the embayment.

Minelot Creek, like Outlet Creek, has lost most of its water to underground streams. However, in the spring, or after a period of heavy rains, you may view the power of Minelot waterfalls.

Here, the Coeymans and Manlius formations are well exposed. Since the Manlius is more subject to erosion, it has been cut back further than the overhanging Coeymans at this point. In time, the large overhanging blocks will fall from the face of the cliff, as evidenced by the large blocks in the creek bed beneath the falls.

If you look towards the northwest, you will see the large embayment along which the trail has led. The "Upper Bear Path" is clearly visible on the portion of the cliff across the Indian Ladder Gulf.

Looking down, the mound at the base of the cliff is called a "talus slope", resulting from the build-up of material broken from the face of the cliff. In earlier times, the talus would have been further broken up and carried away by wind and streams at the foot of the wall. Today, the slopes are becoming increasingly stable due to a growing system of plants.