Geology
Like the Catskills as a whole, a dissected plateau, Balsam was formed not through the uplift of rock layers but by the gradual erosion of stream valleys in an uplifted region about 350 mya. Its rock layers and bedrock are primarily Devonian and Silurian shale and sandstone. Later glaciation, primarily the Illinois and Wisconsin periods, shaped the slopes of the mountain, making them even steeper and gradually forming Esopus Creek from its meltwater.
The steeper slopes and deeper valley on the east side reflect the unusual orogeny of the Esopus and Panther Mountain to the east. The rocks of the stream are fractured and faulted much more than elsewhere in the Catskills, and it and its tributary Woodland Creek make an almost complete circle around the mountain, a rosette pattern similarly unusual in the region. Yngvar Isachsen of the New York State Geological Survey has found evidence strongly suggesting that the entire Panther Mountain region is the inverse form of a crater that formed after an ancient meteor impact when the Catskills were a river delta at the northeastern corner of the inland sea that is now the Allegheny Plateau. The rims of the crater wall were thus more prone to erosion and created a deeper valley for the eventual headwaters of the Esopus.
Read more about this topic: Balsam Mountain (Ulster County, New York)