The area along India Brook shows many signs of the oldest industrial activity in Mendham Township. Near Combs Hollow Road there is a series of iron mines, the shafts of which have caved in leaving depressions. One of the shafts was recorded to be 100 feet deep. There is a stone foundation that anchored a windlass hoist used to pull the iron ore out in carts running on narrow tracks. These mines were worked by the Lewis family into the late 19th century.

Shortly after India Brook enters Mendham Township is the first evidence of the use of its waterpower. The stream makes an abrupt “S” turn, and right at this point is the beginning of a trench on the west side of the stream, which is quite long and obviously hand dug.

Farther along the stream are some shallow pits in the east banks, an indication of efforts to locate iron ore. It was common to locate iron ore by walking up a stream looking for orange rocks that would indicate iron, then digging into the bank to find a vein. Moving downstream on the east side of the bank, there are signs of charcoal burning in areas where bits of charcoal can be found exposed on the banks of the stream and at the base of large trees.

Uphill from the stream, as you walk the Falls Trail, you may see signs of the original Mendham water main. The trail follows the line for some distance. When Mendham Borough created a water company in 1910, it brought the Lewis mill and pond site on Combs Hollow Road and constructed a reservoir. The small concrete building and the ponds behind it were part of the water system. The water line paralleled India Brook to Mountainside Road but is no longer in use.

Farther south on India Brook, there is a breached earthen dam, the site of a large millpond, a sawmill, a forge, and a charcoal house. The Lewis Forge, located just below the dam, was operated by Levi Lewis, who died in 1799. It was reported to be a “one fire mill” utilizing the technology of the Colonial period wherein wrought iron was produced directly from ore in a batch process. The waterpowered trip hammer pounded impurities out of the ore. Waterpower was also used to work the bellows, which supplied an air blast to the hearth to raise its temperature. Charcoal was used as fuel for the forge because it burns at a higher temperature than wood, and it was made right on the site on the east side of the dam. Since charcoal had to be stored out of the weather, a “house” was built into the hill above the dam. Charcoal was deposited on the upper level of the structure and removed on the lower level.

There is a foundation on the hillside east of the dam which may have been the home of the mill workers. An old road ran directly to this site form the Lewis mines upstream and probably continued downstream to the site of Rush Forge in the India Brook Natural Area.

A shortwalk downstream is picturesque Buttermilk Falls, a rock ledge spilling water into a pool that has been a fishing and swimming hole for generations of Mendham Township youth. The falls mark the end of the Combs Hollow Historic District and the beginning of the proposed India Brook Historic District.

Continuing downstream, there is evidence of several millraces cut into the stream. The fall of the water provided enough waterpower to operate a mill by simply diverting water into a millrace by means of a small rock dam. Near this area another stream joins India Brook, fed by several springs from the hill at the Calais Road entrance to Buttermilk Falls Natural Area. On the west side of the stream there is also the beginning of a long hand-dug raceway. There are trees growing on the banks of this raceway that are at least 100 years old. At this point Buttermilk Falls Natural Area adjoins India Brook Natural Area.

About one-quarter mile farther downstream are two stone abutments in excellent condition that carried Steep Hill Road across a steel truss bridge from Mountainside Road straight up to Ironia Road. The road was closed early in the 20th century.

Just north of this bridge was the Rush Forge, which was referred to on an 1823 map as “The Rushes.” This was a one-fire forge built by Michael Rush and appears on the tax assessor’s maps of 1786-1790. It was owned by Jacob Rush in 1809. The Morris Canal maps show it as being abandoned and in ruins as early as 1820. A millpond fed by a small dam was created along the west side of the stream where it would be bypassed by stormwater. Remains of the tailrace from Rush Forge are evident where the race returned water to the brook immediately above the bridge. There are also remains of a dam next to Rush Forge that diverted water from the brook to along raceway west of the trail, leading to the Bockoven sawmill about one-half mile downstream. A foundation can be seen just north of Mountainside Road near the site of the sawmill.