Regarding value, it might be of interest that two of your child’s choices are included in this Forbes article on colleges worth their costs: https://www.forbes.com/sites/nataliesportelli/2017/04/26/10-expensive-colleges-worth-every-penny-2017/.
Note that a Nobel Prize is associated with a graduate of Hamilton’s geosciences department: https://www.hamilton.edu/news/story/hamilton-and-the-nobel-prize. Hamilton’s curriculum in general is notable for its balance. Mathematics, physics, geosciences, creative writing and economics represent some of its stronger programs, for example.
With respect to style of education, Colgate, Hamilton and Bates offer an undergraduate focus with associated access to top professors and laboratory equipment.
Regarding geology itself, Bates offers close access to mostly Paleozoic metamorphic and igneous rocks; at Colgate, Paleozoic sedimentary rocks extend widely to the east and west; Hamilton College rests on Paleozoic sedimentary bedrock and offers proximity to the complex Precambrian metamorphic rocks of the Adirondacks. All of your son’s northern choices offer nearby access to Pleistocene glacial features.