CLINTON GROUP. 
59 
water-courses that we find it disclosed. The whole group has for the most part been so 
denuded as to form no prominent line, but enters into the general equal descent of the country 
toward the lake. 
The harder members of the group appear in all the ravines and water-courses, forming 
rapids, or low falls. These also sometimes appear in the more level country, and are exca¬ 
vated for wall stones. 
The greater part of the group is well developed on a small stream near the former Shaker 
settlement at Sodus bay, and more perfectly, just above the lower falls of the Genesee. At 
this place the mass admits of the following subdivisions, in the ascending order : 
1. Green shale resting on the Grey band, destitute of fossils, very fissile and unctuous. 
2. Oolitic iron ore with concretions, fragments of shells, corals, etc. A few thin layers of impure 
limestone or shaly sandstone, sometimes intervene between the shale and iron ore. 
3. Pentamerus limestone, a siliceous or calcareous amss with thin sandy layers, often having the charac¬ 
ter of shaly sandstone. It also contains bands of hornstone or chert, consisting mostly of silici- 
fied fragments of fossils. This part of the mass is distinctly marked by the presence of large 
numbers of the Pentamerus oblongus, sometimes crowded together, forming a band a foot or 
more in thickness, or distributed through the whole rock. 
4. A green shale similar to that below, though of a less deep color. It also exhibits one or two bands 
of limestone, composed mostly of shells of Atrypa hemispherica, which preserves its beautiful 
pearly lustre. It contains Graptolites, and in some localities where these abound the mass is 
black. 
In this relative situation in Wayne county, the second bed of iron ore occurs. The ore is 
more perfectly oolitic than that below, and with fewer concretions, and usually less carbonate of 
lime intermixed. It appears at Wolcott furnace, and is apparently the bed wrought six miles 
farther east. 
5. A limestone similar to the more calcareous portions of No. 3; and at Rochester containing few fossils 
except crinoidal joints; it is usually thin-bedded, the layers separated by shale; it contains numerous 
cavities filled or partially filled with sulphate of lime, sulphate of baryta, iron pyrites, etc. 
From its situation as the separating mass, it partakes also of the character of the next succeeding 
group. The Niagara, however, being so well characterized, and the Clinton group an ac¬ 
knowledged variable one, it is thought better to place it with the latter. 
The same essential order in the parts of the group appertains to it in several localities in 
Wayne county, but west of the Genesee river two or more of its members are wanting. The 
shale and calcareous matter seem equally persistent, but both gradually diminish westward. 
i. Lower Green Shale. 
This mass is known by its bright green color, and its strong contrast to the subjacent rock. 
It is found in the eastern part of Wayne county, not exceeding thirty feet thick. It is marked 
towards its centre by a band of purple shale at Sodus point, and numerous localities in the 
