How does the book present how did Almashy become aware of the caves?

When we read certain works we have to be aware that there is a sense of ethnocentricism having an influence, i.e. something is not recognized as being known until the White Europeans have "found" and acknowledge that something exists althoughthe natives are well aware of that which has been "discovered" and made known, usually by writings, throughout the world. In the movie there is a subtle reference to the natives knowing that the caves exist because there is a scene where Almashy and a native guide are discussing in a non-English language what Almashy then renders a drawing and text that he includes in his Heroditus. So, how is it represented in the book how Almashy comes to know about the caves.Is it a clear example that Almashy has no previous knowledge that they exist and then comes upon them in his explorations or is there text in the book that follows the movie, i.e. a native source tells Almashy about the caves by providing a phsyical description of the terrain and then Almashy comes across the caves and then they are mapped rather than absolutely no one in the world is aware that these caves exist and Almashy comes across them during his explorations and thus "discovers them because the native did not know they existed? I know from speaking with several of my friends that they miss the detail in the movie that Almashy becomes aware of the caves through his discussion with the native guide. Why many people miss this point is because the conversation is not in English so you need to have non-English language skills. Also, people do not pay attention to the scene because they do not attribute the drawing and text that Almashy renders in his Herotidus and thus the idea prevails as is shown later in the movie that Almashy comes across the caves and thus is the discoverer of them. I contend that in the movie and possibly in the book Almashy is the conduit to being able to map the caves and thus provide others from outside the area their location and thus can be verified that they exist. But I cannot support the view that Almashy in the movie can be considered the discoverer of something that he himself was told by others before he ever saw the caves and thus merely "mapped" them and not "discovered" them. Does the movie represent the same activity line of the cave being known to the natives, Almashy being told about then and then Almashy coming across them and then mapping them for people outside the area? In real life, I can accept that Almashy mapped them but were the caves known to the local natives so the existence of the caves was known by the locls but were verified to exist and mapped for continued verification by Almashy's efforts instead of being the "discoverer" of them?