REPORT OP THE STATE PALEONTOLOGIST 1901 521 



be ascertained at any place. For this area we are therefore 

 compelled to construct from the data brought together from 

 the adjoining territory the probable contact lines, clearly in- 

 dicated in some places by actual exposures and suggested with 

 strong probability in others. 



Medina quadrangle. The country forming the south boundary 

 of the Oak Orchard and Tonawanda creek swamps is likewise 

 barren of any trace of outcrop. The region was carefully 

 traversed from Oakfield, where the gypsum beds of the Salina 

 are extensively wrought, 3 miles to Bumpus triangulation sta- 

 tion, thence west to Wheatville, Alabama and West Alabama, 

 south to South Alabama and Smithville station. It is appro- 

 priate to note from the conditions here displayed by the 

 topography that the great swamp area which extends entirely 

 across this Medina quadrangle rests on the excavated Salina 

 shales or the dolomite series beneath, from which the shales 

 have been removed. 



North from the Tonawanda reservation along the drainage 

 canal running into Oak Orchard creek at a point from If to 1 

 mile south of Shelby where this channel was excavated through 

 the rock, are exposed a succession of the Lockport dolomites. 



Station 27. Where the first east and west road south of 

 Shelby crosses the creek, the lower rock is a bluish gray dolo- 

 mite weathering brown, in thin rough layers from 3-12 inches 

 thick. Fossils occur in this rock, most abundant of which are 

 Zaphrentis and other corals, with Stromatopora. Above this 

 is a band of coarse grained dark dolomite 4 feet thick, some of 

 the layers of which are quite soft and shaly. Here also are 

 found small corals. At the top of this band is a well defined 

 change in the character of the deposition, the rock becoming a 

 more compact and more heavily bedded brown scraggy dolomite. 

 6 to 8 feet of this rock are exposed along the creek for a total 

 distance of about a half mile, and a very large amount taken 

 from the channel six or eight years ago is piled up in heaps on 

 the banks. Just above the bridges on the north and south road 

 the rock dips below the bottom of the excavation but is brought 



