Feathered dinosaur the deciduous sheath, forming a tuft of unbranched barbs with a basal calamus. Stage III consists of two developmental novelties, IIIa and IIIb, as either could have occurred first. Stage IIIa involves helical displacement of barb ridges arising within the collar. The barb ridges on the anterior midline of the follicle fuse together, forming the rachis. The creation of a posterior barb locus follows, giving an indeterminate number of barbs. This resulted in a feather with a symmetrical, primarily branched structure with a rachis and unbranched barbs. In stage IIIb, barbules paired within the peripheral barbule plates of the barb
Calamus Swamp Calamus Swamp Calamus Swamp is a public preserve located from Circleville in Pickaway County, Ohio, United States. It has a natural kettle lake/wetland and is owned by the Columbus Audubon, the local chapter of Audubon. Calamus Swamp includes the only known kettle lake in Central Ohio that is naturally vegetated and undisturbed. The kettle lake was made in the last ice age by the glacier that covered 2/3 of Ohio. When Ada May Burke and Sally V. May got the land, they donated it to Columbus Audubon, who then made it into a public preserve. According to the Columbus Audubon