912 A POPULAR EXPOSITION OF THE 
Fig, 217.—Fenestella elegans Fig. 218.—Orthis ele- Fig. 219.—Spirifer Niagarensts 
(Hall). gantula (Dalman). (Conrad). 
Fig. 220.—S. radiatus Fig. 221.—Dalmannites Fig. 222.— Homalonotus 
(Sowerby). limulurus (Green). delphinocephalus (Green). 
In addition to the above forms, Strophomena rhomboidalis (fig. 
232), Atrypa reticularis (fig. 240), Calymene Blumenbachit (fig. 209), 
with various other species, are likewise more or less abundant. Some 
of the beds of this formation consist in great part also, of broken 
stems and other fragmentary remains of crinoids. 
The Niagara formation (No. 11 in the sketch map, fig. 249) is well 
displayed around the great Falls and along the gorge of the Niagara 
River. The abrupt cliff-face or escarpment, which runs with slight 
interruption from that locality, to Cabot’s Head on Georgian Bay, 
through portions of the Counties of Lincoln, Wentworth, Halton, Peel, 
Simcoe, and Grey, is made up principally of this series of strata. The 
formation constitutes also, Fitzroy Island, the “Flower Pots,” &c., 
together with the southern portion of the Manitoulin Islands—from 
whence, turning to the south west, it extends along the western shore 
of Lake Michigan. Good exposures occur more particularly at the 
