Question:  how many mean elevation with lowest point being Gulf of Mexico and state being Texas
SQL: SELECT COUNT("Mean elevation") FROM "1-1416612-1" WHERE "Lowest point" = 'Gulf of Mexico' AND "State" = 'Texas';

Question: what's the highest point with lowest point being Belle Fourche River at South Dakota border
SQL: SELECT "Highest point" FROM "1-1416612-1" WHERE "Lowest point" = 'Belle Fourche River at South Dakota border';

Question: what's the lowest elevation with highest point being Charles Mound
SQL: SELECT "Lowest elevation" FROM "1-1416612-1" WHERE "Highest point" = 'Charles Mound';

Question: what's the lowest point with highest point being Mount Greylock
SQL: SELECT "Lowest point" FROM "1-1416612-1" WHERE "Highest point" = 'Mount Greylock';

Question: what's the state with highest point being Mount Katahdin
SQL: SELECT "State" FROM "1-1416612-1" WHERE "Highest point" = 'Mount Katahdin';