Salt licks

Popular superstition has it that animals frequent "salt licks" to procure their regular supply of salt. This superstition is held by scientific men who should know better. 
Where are these much-talked of "salt-licks?" I have been unable to find one or to find anybody who has ever known where there is one. I have talked to large numbers of men who have roamed all over the whole of the western part of the U. S., from Kentucky to the Pacific and none of them have ever seen a salt lick. Some of them have never even so much as heard of such things. If they exist, they must be very rare and but a few animals ever have access to them. 
A salt lick, if such a thing exists at all, would be an outcropping of a salt deposit. Salt deposits are not laid down in great numbers all over the world, but are commonly far apart. Rarely, if ever,are there outcroppings of them. This means that salt licks, if they ever exist, are so rare that few animals ever have access to them. Brine springs do exist, but they are not common. Comparatively few animals have access to these.
Mr. Colburn says: "I have diligently inquired of old hunters and pioneers for confirmation of the story that deer and buffalo are in the habit of visiting regularly the salt springs or 'licks,' in order to eat salt. I have not been able to find one who has seen the licking process himself. There is reason to believe that hunters do take their positions at certain brine springs to find their game, and that the deer at certain seasons of the year resort to them - precisely why, is not determined. Nothing of the kind is claimed of the buffalo; that is a tradition."
I myself have been over considerable stretches of this fair land and have never seen a "salt lick." What is more, I have inquired of many old hunters, and have been surprised to find that most of these did not even know what I was talking about. One of these,of whom I inquired, had hunted deer over Texas, New Mexico,Colorado and Arizona and said he had never heard of a "salt lick."
If it is true, as Mr. Colburn seems to think, that deer do frequent brine springs at certain seasons of the year, it is not possible all deer do so, for there are vast stretches of land in this country that are or were, at one time, inhabited by deer, where no such springs exist. This is especially true of the plains country of our great southwest, where a spring of any kind is a novelty.