The Natural Lakes number in the millions as they have been found on all 7 continents. In Antarctica, there are over 400 known lakes beneath the ice sheet that covers that continent. In Alaska alone, there are around 3 million lakes of which the greater part is on the North Slope. The vast majority of all Natural Lakes are shallow (less than 50′ or 15+ meters), but that perceived distance is influenced by human interpretation. At sea level, looking out over a calm ocean, the horizon distance (if your height is 2 meters tall) is roughly 5,000 meters away. This is 3.1 miles distance; not too far. However, take a living human and elevate them to 15 meters (50′) without any railings and now, it is a dangerous height. Inborn fear from falling or immersion into this depth of water increases apprehension. Vertical distances have much more influence on human perception than width or depth. Basically, any water which is over your head (especially to a non-swimmer) is deep water. Natural Lakes seem to limit their depths to 250′ or less. This may be a mathematical relationship between gravity and the physical size and mass of our blue orb. I encourage anyone with the abstract expertise of this language, that I lack, to explore this phenomenon. Ignoring the Oceans, which are in a class of their own and average 2 miles deep, there are 5 variations of lakes that have depths that can exceed this 250′ limit. Again, they are: Reservoirs, usually man made; Rift Lakes, such as all the ones in the Great African Rift Zone; Caldera Lakes; ancient volcanoes that have collapsed or blew out their cores; Mining pits that have filled in with ground water; and the topic of this subject as to what created the Great Lakes of North America: Impact Crater Lakes. I shall discuss my observations as to why this theory is plausible and exhibits more logic to the accepted theory that they have been carved out by ancient glaciers that have visited the North America Continent in its past.