404 



GEOLOGY OF THE SECOND DISTRICT. 



No. 3. The S. nasuta, is abundant in the lower part of the grey sandstone, to be described 

 in the next section. 



No. 4. The Cypricardites modiolaris, is one of the fossils which, along with the Pterinea 

 carinata, appear strictly confined to this rock. Neither of them have left any \estiges in the 

 trenton or utica slate. 



113. 



No. 1. Orthoceratites asqualis. 

 2. Avicula demissa. 



3. Pleurotomaria. 



4. Orthis lestudinaria ? 



5. Orthis crispata. 



6. Tentacuiites. 



No. 1. The Orthoceratites cequalis is quite abundant in the shaly or more sandy part of 

 this rock. A much larger one resembles this, and appears common in the same stratum ; and 

 another also resembhng it, is found one hundred feet below, but it is quite rare. 



No. 2. Avicula deinissa is found in the lower part of the grey sandstone : this is also rare. 



No. 3. Pleurotomaria , occurs in the soft argillaceous mass near the top of the rock. 



No. 4. Orthis testudinaria 1 It is impossible to decide with certainty whether this is the 

 true testudinaria, or the one so called in the trenton limestone. Each figure is a drawing of 

 the different casts, which will be recognized by inspection. 



No. .5. Orthis crispata, is associated with the preceding, but is not so abundant at Loraine. 



The Tentacuiites , is very common in this rock ; at Loraine, it is more abundant near 



the upper part of the rock. 



