Much larger than an elephant

[This is part of a letter I wrote to Ezra Stiles on July 17, 1785:]

I thank you for your information as to the great bones found on the Hudson river. I suspect that they must have been of the same animal with those found on the Ohio; and, if so, they could not have belonged to any human figure, because they are accompanied with tusks of the size, form and substance, of those of the elephant. I have seen a part of the ivory, which was very good. The animal itself must have been much larger than an elephant.