The illustrative map (see link) in the article, Did Ancient Cave Artists Share a Global Language by Frank Jacobs, is very informative. The great diversity and variation of cave symbols found in Europe suggests that the cradle of writing may be in Old Europe; spreading out from there to the rest of the world since remote prehistoric times (when writing was considered a sacred art only practiced by an educated elite class - like the Druids of early historical times, who were hunted down and exterminated by the Romans precisely because they were literate and deeply knowledgeable).
Thirty-two symbols are found in caves of Old Europe, dating to around 40,000 years ago. After Europe, 19 symbols have been found in North America, followed by 18 symbols in Australia, 15 in South America and 14 in South Africa. A few symbols have been found in Southeast Asia and other areas of Africa.
It also appears that the routes of dispersion of symbolic writing may have been primarily by sea rather than over land, starting from Western Atlantic Europe, traveling the sea (or ice bridge) to North America to South America in one wave, and another wave around Western Africa to South Africa, then over to the Oceanic islands and mainland coastal areas of Southeast Asia. To date, these ancient cave symbols have not been found in the Near East or Northern Asia (though many later ancient post ice age alphabets appear to contain forms of and may be derived from the cave symbols of Old Europe).
A rare haplogroup today, the genetic maternal lineage U5b (my maternal lineage haplogroup) is indigenous to Western Atlantic Europe and is also a predominant lineage among the Basques today. Interestingly, rare U5b has been found (the Djehutynakht mummy) in association with the goddess Hathor (also known as the Mistress of the West) and ancient scripts (found in turquoise mining areas of the Sinai) written in a strange mixture of non-classical hieroglyphs and Proto-Sinaitic writing.
Genetic markers are also shared between the U5b-laden Basques and the ancient Sumerians, a non-Semitic group who developed cuneiform writing. Similarly, U5b (Ariche boy) has been found among the ancient Phoenicians, developers of the Phoenician alphabet, thought to be the first true alphabetic script.
Taking all of this together, it becomes increasingly more likely that the true cradle of writing rocks from Old Europe, and more specifically, from Western Atlantic Europe. A deep history mystery speaks to us from the remote past of an ancient sea people indigenous to Western Atlantic Europe, giving us a civilization-building gift of the ability to communicate transferrable meaning over great distances of space and time.