Before I hand over the complete map, let me show you some interesting patterns I discovered while
searching for natron sources.
The Derinkuyu Square
In the region of Cappadocia in Turkey, you can find around a hundred underground cities, each carved into volcanic tuff, all located within an area bounded by four salt lakes. Take a look at the markers!Legend: 
Underground cities 
Endless natron sources
Underground cities
Endless natron sourcesAncient Peru
What's fascinating about Peru is that all the megalithic sites are located several thousand meters above sea level. It's tough to find ancient dried-up seas there. Therefore, these sites are situated around a central natron source, with even the farthest one no more than 40 kilometers from the salt spring, Salinas de Maras.Cusco, Ollantaytambo, Sacsayhuaman, Machu Picchu and all the other lesser known sites are located around the only natron source in these mountains.
Indian Pairs
Across the vast expanse of India, the ancient "stone carvings" follow a different pattern. Here, due to the immense distances, the megalithic sites aren't clustered around a central source. Instead, wherever there's an unlimited supply of natron, you find gigantic ancient "carvings" as well. One lake - one (or more) megalithic site.The coastal areas near Mumbai are the only place where we haven't yet identified a natron source. However, these areas are also accessible by water, so we're not too hung up on this minor hiccup.