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 Creek Bridge Calamus Creek Bridge The Calamus Creek Bridge near Maxwell, Iowa is a concrete Luten arch bridge that was built in 1905. At a cost of $900, it was built by N.M. Stark and Company, a firm which built several Luten arch bridges that are listed on the National Register of Historic Places (NRHP). The Calamus Creek Bridge was listed in 1998. It has a single span and a total length of . The NRHP nomination for the bridge asserts:Before the codification of bridge design in the state in 1913, Stark built perhaps hundreds of Luten arches throughout Iowa, in exclusive