EXPLANATION OF THE PLATES. 365 



PLATE XII. 



Exhibits a view of the Schoharie valley and creek at Gilboa, twenty-five miles above Schoharie court- 

 house. The rocks belong to the Catskill division, and contain many fossils, but of vegetables and 

 inollusca, the latter belonging mainly to the genus Cypricardia. The peculiar vegetation of the 

 Tallies i9 well exhibited; the pendulous elm, and the spreading butternut. The rocks dip only 

 moderately to the southwest The hills are quite steep, and are only thinly covered with grass. 



PLATE XIII. 



Is designed to illustrate some of the topographical features of the Taconic system. For this end I 

 selected Graylock, the highest ground in Massachusetts. Short abrupt ranges seem to have 

 been forced upward, and even appear as if they had been subsequently broken down. In the 

 middle ground the first range is broke down so as to expose the steep slope from Graylock in the 

 distance, into what is called the Hopper. One of the branches of the Hoosic river rises in these 

 narrow gorges. Graylock commands an extended view over the eastern part of New-York, 

 including a part of the Hudson valley and the Catskill ranges. 



PLATE XIV. 



Fio. 1. Nemapodia tenuissima. E. This remarkable impression upon the slate of Washington count5 r , 



has been shown, I think very satisfactorily, by my friend Dr. Fitch, to be formed by some living 



unknown animal. 

 Fig. 2. Gordia marina. E. Body linear, smooth, compressed ; convolutions or folds like the Nereites. 



The animal seemed to be destitute of knots or ganglia. It occurs in the quarries of flagging stone 



in Jackson, Washington county. 

 Fig. 3. This is a fragment merely of a crustacean of a doubtful character, or it may be a part of a 



nereite. It was the first fossil which was found in Washington county, which belonged to the 



animal kingdom. 



PLATE XV. 



Fig. 1. Nereites jacksoni. E. Feet large and orbicular : Waterville, Me. 



Fig. 2. N. pugnus. E. Feet large, rather long and ovate. It terminates in an enlargement which 



resembles the fist. See fig. 4, Plate 16. Waterville, Me. 

 Fig. 3. N. loomisi. E. Feet numerous, small, lanceolate : Waterville, Me. 



PLATE XVI. 



Fig. 1. Myrianites murchisoni. E. Long, linear or threadform, and slightly knotted ; folds numerous. 



Fig. 2. Nereites deweyi. Feet oval, numerous. 



Fig. 3. N. gracilis. E. Feet narrow, thickly implanted ; long, ovate. 



Fig. 4. N. pugnus. Showing the termination. 



Fig. 5. M. sillimani. E. The body is larger than the M. murchisoni, but the knots are quite similar 



to it. 

 Fig. 6. N. lanceolata. Feet lanceolate. 



PLATE XVII. 

 Exhibits the pelagic fucoids of the roofing and taconic slates of Rensselaer and Washington counties. 



