Bull. U. S. F. C. 1897. (To face page 426.) 
Plate XV. 
WISCONSIN PEARLS. PINK, COPPER-COLORED, AND BROWN. 
Group B. Under side of j 
TWISTED AND RENIFORM PEARLY GROWTHS, SOME SHOWING GROUPING OR COALESCENCE. 
Nos 5, 7 Plain spirals. 
No. 4. With central nucleus, the layers finely sh >wn in Group B. 
Nos. 15, 19. Elongated spirals. Nos 12, 20. Well-marked coalescence. No. 17. Hook-shaped growth. 
Very brilliant mass, grouped above and running 1o a sharp point, in form suggesting a coral-polyp. 
