B. Smith — New Locality for Castoroides. 465 



out this stretch it is overlaid by the peat or muck. Locally 

 thin bands of marl intervene between the basal Cowaseion 

 Clay and the muck. In places the muck itself is covered by a 

 sandy soil which may possibly represent stream wash from the 

 originally meandering Cowaseion Creek. 



In the vicinity of Oniontown,* about five miles northwest of 

 Canastota, the basal stratum in the creek bank is no longer 

 clay but a light colored shell marl. Possibly the Cowaseion 

 clay passes into this marl by lateral transition, but it is believed 

 that the clay dips under the marl. The marl is overlaid by the 

 dark peaty muck. These two formations are apparently con- 

 tinuous for a distance of two or three miles in a northwesterly 

 direction. 



About two miles below Oniontown the creek bends sharply 

 toward the north. Just beyond this turn the section shows in 

 descending order muck, marl, and a grayish or bluish clay. 

 The marl is now quite thin. The basal clay is here the inter- 

 esting member for it is highly probable that it represents the 

 Cowaseion clay returning to the surface. 



On following the northern portion of the creek to its mouth 

 at Lakeport on Oneida Lake, it is found that all of the above 

 described formations disappear. The banks, which are now 

 cut through higher and more irregular ground, show only 

 bowlder clay at base capped by a reddish laminated clay. 

 Except for a few feet of Paleozoic bed rock at Lakeport, these 

 latter formations are the only ones encountered in the lower 

 stretches of the creek. 



Though the investigations so far undertaken are of an 

 admittedly preliminary character the evidence points to the 

 conclusion that the Cowaseion Clay (yielding Castoroides) and 

 the shell marl were both deposited in a shallow water body 

 slightly higher than the present Oneida Lake and probably 

 cut off from it by the barrier of glacial deposits which have 

 just been mentioned as occurring south of Lakeport. Bluish 

 clay is the basal formation at the northwest end of the section 

 through this hypothetical lake. A considerable stretch at the 

 southeast end of the section is likewise underlaid by bluish 

 clay (the Cowaseion Clay). It is, therefore, believed that the 

 Cowaseion Clay passes under the marl and that the two 

 deposits represent consecutive stages in the shallowing and 

 contraction of the lake. The almost universal capping of peat 

 or muck illustrates the final or swamp stage which caused the 

 extinction of the water body, and which was only terminated 

 by the drainage ditches of civilized man. 



*See U. S. G. S. Topographic Sheet of the Chittenango Quadrangle. 



