58 
GEOLOGY OF THE FOURTH DISTRICT. 
10. CLINTON GROUP. 
Lower part of the Protean group of the Annual Reports ; Ferriferous slate, and Ferriferous 
sandrock of Eaton. 
(Part of No. 5, Pennsylvania Survey.) 
This group is one of variable character, consisting of many kinds of deposits, which are 
not uniform either as to composition or continuation. From this circumstance it first received 
the name of Protean. This term, also, at that time included the Niagara group, which 
appears a thin mass in the Third district; but from its greater development and distinctive 
features in the western portion of the State, that has been separated. 
The term Protean is still applicable to this assemblage, which in some places consists of 
thin shaly sandstones, shales, and even conglomerates ; in others, of thin-bedded, impure lime¬ 
stones, shaly sandstones, iron ores, etc., with scarcely any fossils except Fucoides; still 
again it appears as a duplicate series of shales, limestones and iron ores, with some inter¬ 
mixture of sandy matter, all containing abundance of marine shells; and lastly, it presents 
itself on the extreme western margin of the State, as a single bed of shale and limestone, 
with rarely a fossil of any kind. From its superior development near the village of Clinton, 
in the Third district, it has received that name. 
It will be seen that this formation, which is colored green upon the map, extends across 
the district in a nearly east and west direction, occupying a narrow belt of country just above 
and to the south of the Medina sandstone. Its greatest width within the district is in Wayne 
county, and it thins gradually towards the west. Through the greater part of Wayne county, 
this formation ranges within two miles of the lake shore. Crossing the Genesee below 
Rochester, it forms for a few miles a low terrace on the north side of the canal, known along 
that distance as “ the Little Ridge.” After that it is seen on the south side to within eight 
miles of Lockport, wdiere the canal is excavated in the rocks of the group; thence westward 
it appears near the base of the limestone terrace, forming part of the slope. Beyond the 
Niagara river, in Canada, it can be traced, still of the same character as within the State ; and 
it probably follows the associated rocks through the peninsula. 
This formation exists in Ohio, though not so distinctly developed as in New-York. Dr. 
Locke has detected some of the peculiar fossils, as well as the iron ore, in Clinton county of 
that State ; and from numerous other facts, it appears to have a wide range and very variable 
lithological character. In Pennsylvania the whole formation is greatly thicker than in New- 
York ; but the products bear a close resemblance. It is there known as the “ red and varie¬ 
gated shales and sandstones.” 
From the destructible nature of its lower member in the Fourth district, it has usually 
receded some distance from the outcropping edge of the sandstone, and it is only along the 
