The Appalachian Range is nowhere to be seen. The mountains of the American West have some major differences. For starters, only the Rockies stand firm — no Coast Range, no Grand Canyon, no Cascades, no Alaska Range and most certainly no Sierra Nevada. While our Rockies stand no taller than 14,440 feet above sea level, the tallest peak in a Great Lakes Rockies is measured to be 20,310 feet. Back home, our Rockies formed between 80 and 55 million years ago through the Laramide Orogeny, the subduction of the North American and Pacific Plates at a shallow angle. Their Rockies first formed 80 million years ago as the result of a collision between eastern and western North America. They stopped becoming active as recently as 30 million years ago. The main rocks of the range are schist, granite and gneiss, tough rocks with small vulnerabilities. No wonder, then, that transdimensional explorer Mark Greene called the Great Lakes Earth Rockies “a single, continuous spine of breathtaking Tetons.” West of the Rockies, which could vary in width between 75 and 300 miles, stands a plateau varying in elevation above sea level between 3300 and 16,000 feet. Encrusting the plateau at the top is an igneous province of basalt, half a million square miles in area, 512,000 cubic miles in volume and over 6500 feet at the thickest, the result of lava flooding western North America 65 million years ago. Without the Cascades or the Alaska Range, the distinctively whiplike Alaskan Peninsula simply does not exist. The Yellowstone mantle plume is still present. Except that instead of Wyoming’s northwestern corner, it can be found in northeastern California. The upland itself covers an area of 5,000 square miles and stands almost like an island between the surrounding lakes and lowlands. Five million years ago, a landbridge formed, connecting North to South America, completely rearranging global ocean currents. The Gulf Stream now traveled high up to the Arctic, bringing moisture that would later become ice. The Twins, as they are called, are still active, but both are tall enough to censor migration. One twin is currently 6,684 feet above sea level, the other 9,698 feet. Combined, this reduced the Great American Interchange in comparison to the one back home. True to the spirit of the planet’s name, North America is full of large lakes. The largest of which is Agassiz. In fact, it is the cornerstone of all of Great Lakes Earth’s great lakes — enormous depressions, tectonic rifts or volcanic calderas reshaped and filled in by ice, rain and river. To have an idea on the shape, size and scope of Agassiz, we must look at the familiar faces of the Great Lakes — Superior, Michigan, Huron, Erie and Ontario — and then flood off the entire basin. This is Lake Agassiz, 95,000 square miles and 5500 feet at its deepest. Agassiz started out as a few tectonic depressions that expired some 20 million years ago. They wouldn’t become one lake until the ice bulldozed the depressions during the Pleistocene glaciations. There are great lakes west of the Rockies, as well. (The map does not take rivers into consideration.) The Black Hills of South Dakota don’t exist on Great Lakes Earth. The Ozarks, larger in area and elevation, are the closest analogy. Comparing their South America to ours, there’s not much difference to find. The Andes themselves, though equal in length and width to our own, are taller and more active — the highest currently stands 30,111½ feet above sea level (not 22,841, as was the case back home) and the annual average of volcanic eruptions measures in at 50 per century. How would any of these changes affect the climate, weather and landscapes of the New World?