In a bowl, combine gingersnaps and graham crumbs with 1/4 cup sugar and butter. Press into bottom of a 9" springform pan. Bake at 350° for 8 to 10 minutes.
In a mixing bowl, beat cream cheese until smooth. Gradually add one cup sugar; beat until light. Add eggs, one at a time, beating well after each.
Transfer 1 1/2 cups of cream cheese mixture to a seperate bowl and blend in pumpkin and spices. Pour half of pumpkin mixture into prepared pie crust. Top with half of cream cheese mixture. Repeat layers using remaining pumpkin and cream cheese mixtures.
Using a table knife, cut through layers with uplifting motion in 4 to 5 places to create marbled effect. Bake at 325° for 45 minutes without opening oven. Run knife around sides of pan to remove sides before releasing springform. Cool and store in refrigerator. Top each serving with a dollop of whipped cream and additional nutmeg.