XII 
CONTENTS, 
CHAPTER V. 
NEW-YORK SYSTEM. 
Description of the rocks and groups of the New-York system, embraced within the Fourth Geolo¬ 
gical District. 32 
9. Medina sandstone. 34 
1 . Red marly or shaly sandstone.... 36 
2. Grey quartzose sandstone. 37 
3. Red shale and sandstone.. 38 
4. Greenish-grey argillaceous or sili¬ 
ceous sandstone. Grey band of 
Eaton. 39 
Diagonal lamination. 40 
Accretions. 41 
Localities.. 42 
Thickness. 43 
Mineral contents. 44 
Springs.. 44 
Agricultural characters. 45 
Organic remains . 46 
Ripple marks. 49 
Shrinkage cracks .. 51 
Sandy beach and stranded shells. 52 
Wave lines .... 54 
10. Clinton group. 
1 . Lower green shale. 59 
2. Oolitic or lenticular iron ore. 60 
3. Pentamerus limestone of the Clin¬ 
ton group. 62 
4. Second green shale. 64 
5. Upper limestone. 65 
Localities. 66 
Thickness... 66 
Mineral contents of the group. 67 
Organic remains. 68 
Localities of superposition. 78 
11. Niagara group. 79 
General features, extent, etc. 80 
1 . Niagara shale. 81 
2. Niagara limestone. 84 
Concretionary structure. 86 
Topographical features... 96 
Localities. 96 
Thickness. 97 
Mineral contents of the group. 98 
Springs . 99 
Agricultural characters. 99 
Organic remains. 100 
12 . Onondaga salt group. 117 
Subdivisions. 119 
Localities. 132 
Shrinkage cracks. .. 133 
Minerals. 134 
Sulphuric acid. 134 
Brine springs or salines. 134 
Agricultural characters. 136 
Organic remains. 137 
Localities of superposition. 139 
13. Waterlime group. 141 
General characters and localities 141 
Organic remains. 142 
Waterlime or hydraulic cement. 142 
14. Pentamerus limestone. 144 
15. Delthyris shaly limestone.... 144 
16. EncRINAL LIMESTONE. ... .. 145 
17. Upper PENTAMERUS LIMESTONE .. 145 
18. Oriskany sandstone. 146 
Its development and localities in the 
Fourth District. 146 
Organic remains. 1 47 
19. Cauda-galli grit. 150 
20 . Schoharie grit. 151 
21 . Onondaga limestone. 151 
