32 



LOWER PENINSULA. 



group of Alpena. Fig. 4 is from the corniferous limestone at Port 

 Colborne, C. W. 



FAVOSITES RADIATUS, N. Sp. 



Tubes unequal, rounded-polygonal, one and a half to two and a 

 half millimeters in width, radiated by twelve prominent rows of 

 lateral squamae with intervening deep linear furrows. Diaphragms 

 simple, straight, or warped by marginal, siphon-like depressions ; the 

 pores are numerous, forming from one to three rows on a side. A 

 small pit surrounds each of them, as in Favosites tuberosus. The 

 tubes of some specimens exhibit the lateral rows of squams only 

 in rudimentary development, and are nearly smooth on the inside, 

 with flat, moderately distant diaphragms. In other specimens the 

 squamae project with their elongated linguiform apices nearly to 

 the centre of the tubes. 



Grows in large convex masses. Found in the Hamilton group 

 of Thunder Bay, also at Eighteen-mile Creek, near Hamburg, N. Y. 



Plate X. — Fig. i, surface view of a partly silicified fragment of a 

 larger convex mass, found in the Hamilton group of Alpena. 



FAVOSITES NITELLA, Winchell. 



Tubes rounded-polygonal, subequal, stout-walled, not fully one 

 millimeter in width. Tube channels smooth or beset with distant 

 lateral squamae. Diaphragms partially simple, regular, partially of 

 complicated, irregular form, through intersection with the lateral 

 squamae. Pores large, distant, in a single row on each side. Mode 

 of growth globular or pyriform or digitato-ramose. Resembles in 

 structure Favosites Hamiltonensis, differing from it only by much 

 smaller tube size. 



Plate XI. — Fig. 4 represents specimens from the blue shales of 

 the Hamilton group of Little Traverse Bay. Similar specimens are 

 found in the Hamilton strata of Thunder Bay. . 



FAVOSITES PLACENTA, N. Sp. 



Tubes less than one millimeter wide, rounded-polygonal, sub- 

 equal or unequal, larger tubes and smaller tubes clustered to- 

 gether in separate spots, or single circular tubes dispersed between 



