Report 67425: Possible vocalization 4 miles north of Pawling, heard from Appalachian Trail

On March 18th, 2018, I was hiking alone at night on the Appalachian Trail off of Route 22 in Pawling,NY.  I was heading up Corbin Hill towards Cat Rocks, near West Mountain.  I started just before sunset, around 7pm. On my return trip down Corbin Hill, around 9pm, I heard a loud vocalization that I could not identify. It was a loud scream, lasting about 15 seconds. It started low-pitched as a howling "oooooh" sound, then got higher pitched as an "aaaah" sound.  It didn't sound like an owl or coyote, but more like a primate.  Based on my internet research, it sounded most like a gibbon's call, but deeper.  I heard no further vocalizations. I cannot confirm that what I heard was a Sasquatch, but I felt it was important to report.