2 8 LOWER PENINSULA. 



come anchylosed with them and disturb their regularity, but never 

 to the same degree as in the former species. Connecting pores 

 large, forming a single row on each side. Rows of lateral squamae, 

 in some specimens very \vell developed. Other specimens or por- 

 tions of specimens have smooth tube channels. Mode of growth 

 globular, or tuberose, or in coarse ramifications, often incrusting 

 other bodies with the basal portion. Abundantly found in the 

 Hamilton group of Thunder Bay and Little Traverse Bay, and in 

 the drift deposits. 



Plate VII.— Fig. 3 is a specimen from Stony Point, Thunder Bay. 

 Fig. 4 is found in the limestone bluffs of Petosky, presenting a 

 vertical section through a specimen identical with Winchell's 

 Favositcs diunosiis, which is often found in more slender ramifica- 

 tions, but also in rounded, tuberose form, in no way differing from 

 the typical specimens of Hamiltonensis. Favositcs Billingsii I have 

 named a form nearly related to F. Hamiltonensis, which is the pre- 

 vailing species in the Hamilton strata of Widder, C. W., and in 

 the Hamilton group of New York. It grows in large lenticular 

 disks, sometimes three feet in diameter ; the lower side has a 

 central point of attachment and is covered by an epithecal crust. 

 Tubes rounded-polygonal, unequal, from two to three millimeters 

 wide. Diaphragms flat, with marginal, punctiform depressions, 

 similar to Favos. alveolaris, Goldfuss. Pores forming a single row 

 on each side. Lateral squamae rudimentary or absent. Not 

 figured. 



FAVOSITES EPIDERMATUS, Rominger. 



Vide " Silliman's Journal," November, 1862. 



Tubes from two to three millimeters wide, subequal in the same 

 specimens, of obtusely polygonal outlines. Tube channels longitu- 

 dinally striate by a cycle of twelve well-marked furrows, each of 

 the intermediate band-like spaces bearing a row of horizontal 

 squama.', sometimes very prominent, and at others in rudimen- 

 tary condition and partially obsolete. Diaphragms simple, flat, 

 or warped by marginal depressions, more rarely of broken, angu- 

 lar surface through complication with the lateral squamae, as 

 in Favositcs hemisphcricus. Pores comparatively small, surrounded 



