Amherst sends a lot of people on to graduate scale (as a percent of their overall enrollment) - a lot of LAC’s do. It is well-regarded by graduate schools.
You might be interested in these resources:
- NSF article detailing the universities and colleges that send the most students onto get doctorates in science. About 1/2 of the top 50 are LACs:
http://www.nsf.gov/statistics/infbrief/nsf13323/
- Reed also provides a shorter list which ranks schools by the percentages of students who go onto get doctoral degrees in a variety of disciplines: