Broadway Avenue is similar to Audubon Avenue - both are large to immense, mostly breakdown-filled canyon passages at Mammoth Cave's level B (both have >80' worth of unlithified material filling the passages). Broadway Avenue extends to the southeast from the Rotunda Room. It ends at the intersection with Gothic Avenue. At this point, the main southeast-trending cave passage drops in elevation a bit. That's the beginning of the Main Cave.
The limestone walls of Broadway Avenue between the Rotunda and the Methodist Church have often been referred to as the Kentucky Cliffs. The lower Girkin Limestone makes up the ceiling and upper walls while the lower cave walls consist of upper Ste. Genevieve Limestone.
Four regular cave tours take visitors through Broadway Avenue: “Historic Tour”, “River Styx Tour”, “Star Chamber Tour”, and “Violet City Tour”.
In early days, numerous bats could be seen in Broadway Avenue, just southeast of the Rotunda. Modern bat populations are highly reduced in comparison.
Heading southeastward from the Rotunda, along the Kentucky Cliffs and toward the upstream direction of the ancient underground river, the entrance to the Corkscrew is encountered along the northeastern cave wall, well above floor level. The Corkscrew was an early shortcut down to or up from River Hall, which leads further down to the modern water table & the modern underground river. Modern public cave tours don't use the Corkscrew. During after-hours times, some current cave employees get the chance to experience the unique adventure that the name “Corkscrew” implies.
Corkscrew Entrance/Exit (looking ~NE) (from an old postcard; original photo by Benjamin Hains) - tour group descending from the Corkscrew entrance along Broadway Avenue.
The Corkscrew has been described as a domepit mostly filled with limestone breakdown or as a twisted, steep, narrow canyon passage mostly filled with limestone debris. The earliest visitors climbed and crawled through the Corkscrew. Step-ladders were installed afterward.
The following descriptions from early Mammoth Cave literature helps one appreciate this feature: “The Corkscrew is an intricate web of fissures. . . “ and “[The Corkscrew] is a gap in the wall into which you can scramble and make your way down a chaotic gulf, creeping like a rat, under and among loose rocks, to the depth of 80 or 90 feet - provided you do not break your neck before you get half-way.”
Corkscrew (from Hovey & Call, 1912)
Methodist Church (looking ~SW) (from an old postcard) - just southeast of the Corkscrew entrance, Broadway Avenue intersects with Archibald Avenue, a gigantic, mostly debris-filled canyon passage. Archibald Avenue is the downstream continuation of Gothic Avenue. This intersection is called the Methodist Church. Church services were sometimes held in this room in early days. Attendees were likely attracted by the novelty of underground services, the coolness of the cave during hot summers, the warmness of the cave during cold winters, and the potentially emotionally-moving acoustics.
Breakdown-filled Archibald Avenue is behind & to the right of the photographer. Broadway Avenue extends to the right & left of the old wooden tulip poplar pipes from the 1810s saltpetre mining operation.
Notice the curved edge of eroded limestone beds in the ceiling of Methodist Church. The pattern indicates original underground river flow direction.
The earliest river flow direction at this locality was from Archibald Avenue toward Broadway Avenue (into the photograph & to the right in the distance), and onward toward the Rotunda. After that, Archibald Avenue was bypassed, and the river's flow direction was along Broadway Avenue only (again heading to the right in the distance, toward the Rotunda).
Girkin Limestone occurs at the ceiling & upper walls of Methodist Church. The Ste. Genevieve Limestone occurs along the lower walls.
Broadway Avenue (looking NW) - the viewer is facing toward the old downstream direction when an underground river used to be here (when level B was flooded). The river flowed to the NW toward the Rotunda Room.
Approximately the upper half of Broadway Avenue's walls has rocks of the lower Girkin Limestone. The lower half of the walls has upper Ste. Genevieve Limestone beds. The ceiling tends to be moderately smooth & flat, water-worn limestone bedding planes.
Wooden Pipeline - hollowed-out tulip poplar tree trunks near the Methodist Church. These were used to pipe water to a 2nd set of saltpetre leaching vats.
Saltpetre Leaching Vat - this 1810s wooden structure is part of a 2nd set of saltpetre leaching vats (“hoppers”) located at the intersection of Broadway Avenue & Gothic Avenue. The 1st set of leaching vats is in the Rotunda Room. Additional piles of leached cave dirt occur in the vicinity of the 2nd set of vats.
Gothic Avenue & Booth's Amphitheater (looking ~SE) (from an old postcard; original photograph by Ray Scott & J.W. Young) - Broadway Avenue starts at the Rotunda and ends here, at the intersection with Gothic Avenue (the cave passage at the top of the stairs). The Girkin Limestone-Ste. Genevieve Limestone contact is a little above the top of the stairs.