Megalonyx: Lion or Sloth?

This is from my letter to Col. John Stuart, August 15, 1797:

With great pleasure I forward to you the Diploma of the American Philosophical Society, adopting you into their body. The attention on your part, to which they are indebted for the knowledge that such an animal has existed as the Megalonyx, as we have named him, gives them reason to hope that the same attention continued will enrich us with other objects of science, which your part of the country may yet, we hope, furnish.

On my arrival at Philadelphia, I met with an account published in Spain of the skeleton of an enormous animal from Paraguay, of the clawed kind, but not of the lion class at all; indeed, it is classed with the sloth, ant-eater, etc., which are not of the carnivorous kinds; it was dug up 100 feet below the surface, near the river La Plata. The skeleton is now mounted at Madrid, is 12 feet long and 6 feet high. There are several circumstances which lead to a supposition that our megalonyx may have been the same animal with this. There are others which still induce us to class him with the lion. Since this discovery has led to questioning the Indians as to this animal, we have received some of their traditions which confirm his classification with the lion.

As soon as our 4th volume of transactions, now in the press, shall be printed, I will furnish you with the account given in to the Society. I take for granted that you have little hope of recovering any more of the bones. Those sent me are delivered to the society. I am, with great esteem, dear Sir, your most obedient servant.

[Note: It was later named in my honor, as Megalonyx jeffersonii.]