136 Geological Equivalents. 



JYames of straia which are known to Geologists of both Continents, 

 ivith some of their organic associations in JYorth America. 



I. PRIMITIVE. 



Gneiss, slaty granite, ") 



Granular q,uartz, > Absence of all organized remains. 



Granular limerock. } 



11. TRANSITION. 



Argillite. 



Clay slate. Orthocera, Filices. 



Wacke slate. Terebratula, (species not yet ascertained.) 



First graywacke. 



Millstone srrit, ) ,t- . , • t i 



Old red sandstone. \ ^° organized remains discovered. 



Metalliferous limerock. 



Mountain, Encrinal. Encrinus transversus. 



Shelly. Fungites polyraorpha, 'Calymena Blumenbachii, Ortho- 

 cera annulata, O. striata, O. undulata, Spirifer arabiguus, Os- 

 trea, (nine inches long and three wide,) "Asaphus, (large,)* 

 I Ogygies latissimus, (found in a lias-like rock, between the 

 shelly and cherty limerock.) Fungites discoidea, Columnaria 

 sulcata, Productus heraisphericus, Scalaria semicostata, Encri- 

 nus curvatus, iiithodendron dichotomum. 



Cherty. Cyathophyllum ceratites, C. vermiculosum, C. flexuosum, 

 C. vesiculosum, C. helianthoides, C. quadrigeminum. This gives 

 us six species of the Cyathophyllum, which we have found in the 

 cherty or cornitiferous limerock. These horns, as they are call- 

 ed, (Ceratites, stone-horns of authors,) and the hornstone, entitle 

 the rock to the appellation Cornitiferous. Orthocera paradoxica, 

 Conularia quadrisulcata, Productus depressus, Gorgonia ripeste- 

 ria, Gryphea Macullocha, Terebratula dirnidiata, T. octoplicata, 

 T. pectita? T. affinis? Spines of an Enchinus in abundance; 



* This is found in the upper soft slaty variety of the rock, which has been so suc- 

 cessfully used for the lias cement at Chitteningo, &c. Dr. Smith, of Lockport, sent 

 me two specimens, taken from a continuation of the Chitteningo lias rock, immedi- 

 ately beneath the geodiferous limerock, on which the cherty (cornitiferous) reposes. 

 For a temporary name, I call it Ogygies latissimus. It contains twenty five joints; 

 side lobes one half as broad as middle lobe ; and the latter, half as wide as long : 

 joints of the middle lobe curved obliquely backward and then forward at its edges, 

 and extend to such a depth as almost to sever the side lobes. Its middle lobe is five 

 inches and a half long. Remains of the original crust or shell appear to be present 

 in one of the specimens; which are dark colored or black, and separated by double 

 white lines of carbonate of lime. The dark colored part seems to be a substitution 

 from the rock. 



