There were a number of stereoscopic views of this area manufactured in the 1860s and 70s. This is pretty much how things looked when Frederick Law Olmsted and his family lived here, 1859-1862, while Olmsted was directing the construction of Central Park.
This view from East Drive is recognizably the same “Mount” you see today when you go to the composting area. The buildings are long gone, but the driveway and topography are unmistakable.
Best of all, we can see a bit of the McGown House, the 1790 rebuilt version that became the Mount St. Vincent’s complex. It’s the small, recessed building in the middle, with what looks like a vast awning but is no doubt part of a pitched roof. The big south wing (on our side) and the north wing (far side) were the first expansions of the convent, built in 1847 and 1848. It appears that a extra story was added to the top of the farmhouse, connecting the upper floors of the two wings, so the nuns and others wouldn’t have to descend to the ground floor in order to move from one wing to another.