1870.] ' '±^<3 [Meek and Hayden. 



Ne. Feet. 



15. Sandstone, steel grey, 12 



16. " in thin layers of variegated colors, 5 



17. " steel grey, in layers (contains streaks of coarser yel- 



low in layers), 35 



18. Shale, Brown, , . 3 



19. Sandstone, Yellow, 6 



20. Shale, Brown, 1 



21. Sandstone, Steel grey, 40 



22. " White, 6 



23. Sandstone, Grey, 4 



24. Shale, earthy, Black, 1 



25. Gypseous earth, Yellow, -5 



26. Shale, Black, .5 



27. Sandstone, contains shells in fragments, 15 



28. Shale, Brown, 1 



29. Clay, marly, 1.5 



30. Sandstone, Yellow, ' 30 



31. Shales and clays, earthy, 25 



32. Shale, Brown, 6 



33. Sandstone and Gypseous earth, 20 



34. Shale, Bituminous, 1 



35. Gypseous earth, 3 



36. Sandstone, yellow, 10 



37. " white, 8' 



38. Marl, contains shells, 6 



39. Gypseous earth, 2 

 To end of Cut, Shale, clay, and arenaceous Gypseovis earth, 60 



Length of cut, 440 feet. 



A Prelimhstaky List of Fossils, collected by Dr. Hayden in Colo- 

 KADO, New Mexico and California, with Brief Descriptions 

 OF a few of the New Species. 



By F, B. Meek. 



Read before tlie American PMlosopMcal Society, May 6, 18T0. 



Silurian Species. 



Camp Greek Canon, Colorado City. 



1. Orthis Color ado ensi?. Meek. 



A small, comi)ressed, nearly equivalve, subsemicircul species, much 

 widest on the hinge line, which is sometimes abruptly produced into late- 

 ral auricles. Dorsal valve less convex than the other, and having a shal- 

 low, rather wide, mesial sinus, rapidly narrowing to the beak, which does 

 not project beyond the hinge line. Ventral valve depressed convex, with 

 cardinal area rather low, flat, inclined backward, and sharply defined to 



