what's the lowest point with highest point being mount greylock
CREATE TABLE "table1_1416612_1" (
  "state" text,
  "highest_point" text,
  "highest_elevation" text,
  "lowest_point" text,
  "lowest_elevation" text,
  "mean_elevation" text
);
SELECT "lowest_point" FROM "table1_1416612_1" WHERE "highest_point"='Mount Greylock';