Amboy is actually the eastern outpost of several Quaternary volcanic centers on the Route 66 corridor within California.  Approximately 8 miles west of the Amboy Lava Fields lies the Bagdad Cone Complex, a group of four agglutinate cones not much older than Amboy.  These craters are interesting in that the lavas brought up chunks of unmelted mantle rock.  Directly south of this field is the Ordnance Cone Complex, of a similar age.  Farther west, I-40 crosses the extensive Pisgah Lava Field.  The cinder cone of this field was mined for cinders at one time.  Directly across Lavic Lake (dry) from the Pisgah Field is the Lavic Flow and the Sunshine Cone Flow.  K-Ar dates for these flows are approximately 800ky and 200ky respectively.  Still farther west, in the Rodman Mountains, lies the Malpais Flow and associated cinder cone.  The cone here was also quarried at one time. 

 Other Quaternary volcanic centers are scattered throughout the Mojave.  One good example is the Cima Volcanic Field, south of the town of Baker, on the I-15 corridor.