Carnegie Inst. Washington Pub. 289, Vol. Ill— Douglass 



A.D. 611 615 



620 



PLATE 8 



O 



Enlargements of specimens shown in frontispiece. 



A. MLK-179, showing JCD signature, A.D. 611 to 620. 



B. MLK-127, showing same. 



C. Center of MLK-179: the microscopic ring at center is A.D. 536; it is the small ring, 

 fifteenth ring from the center, in MLK-127. 



