Plate 13. 



Surface of a slab of limestone from the Wassalem beds, illustrating the abundance of 

 fossils in this formation. The large, reticulate specimen with a solid, spreading base, 

 in the middle portion of the plate, is of the abundant Eomotrypella cribrosa, the ribbon- 

 like, cribrose frond in the upper part of the plate represents Graptodictya proava; a 

 fragment of Favositellaf punctata lies just below the center of the plate. Most of the 

 slender, ramose specimens are young examples of Dittopora colUculata. 



"Wassalem beds (D3), Uxnorm, near Reval, Esthonia. 

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