Especially refering to Birch Pass buildup.
Tubular form. 
Paleoaplysina, Eugonophyllum, Archaeolithophyllum and tubular forams are important.
Maximum thickness 16 m.

Abstract of ref. 261:
The plate-shaped calcareous hydrozoan ? Palaeoaplysina Krotov is the main fossil in Late Pennsylvanian and Early Permian carbonate buildups in the Lemhi Range and Arco Hills of east-central Idaho (USA) Palaeoaplysina has an internal subparallel canal system imbedded in cellular tissue, and mamelon-like surface protuberances. Other fossils in the buildups include the calcareous phylloid alga Eugonophyllum, other unidentified phylloid algae, crustose bryozoans, and less common gastropods, crinoids, and brachiopods. Buildup sediment accumulated primarily by the baffling and entrapment of loose carbonate pellets, lime mud, and skeletal fragments in protected pockets and hollows
between Palaeoaplysina and algal plates. There is a continuum between tabular and lenticular buildup geometries.
    Broad tabular buildups are typically 2-10 m thick and as much as 15 km wide. The basal surfaces of the tabular
buildups conform to previous sea-floor topography, whereas upper surfaces are relatively flat and planar, suggesting that the buildups were limited in upward growth because they formed in the uppermost subtidal zone. The abundance of porcelaneous tubular foraminifers (resembling apterrinellids and Hedraites), which encrusted some unpreserved organisms, suggests that some buildups were carpeted by unfossilized vegetation such as noncalcareous algae. Strongly
lenticular buildups are typically 2-16 m thick and a few tens to hundreds of meters wide. Most were large enough to modify depositional conditions nearby, resulting in fore-mound and back-mound beds. All of the lenticular buildups, and some of the tabular ones, stood topographically above the adjacent sea floor while they formed. Some buildups are stacked one above another. Others are in offlapping sequences which also include lenticular beds of crinoidal-bryozoan lime wackestone and grainstone. 