Santa Ana River Hydroelectric System, Aqueduct, Redlands, San Bernardi...
Survey number: HAER CA-130-T Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Domestic Water Supply Trea...
Survey number: HAER CA-130-H Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powder Magazine, Redlands,...
Survey number: HAER CA-130-M Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Sandbox, SAR-1 Bypass, Redlands,...
Survey number: HAER CA-130-N Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Public takes a look at Santa Ana River Marsh study
An environmental restoration project will remove 50,000 cubic yards of material from a marsh at the mouth of the Santa Ana River, improving degraded habitat that has adversely affected endangered species that u... More
A body of water surrounded by trees on a sunny day. Lake jenks lake bl...
A lake with trees and a blue sky / A lake in the mountains public domain stock photo. A lake with trees and a blue sky / A lake in the mountains public domain stock photo.
Eileen Takata, landscape architect, lead water resources
Eileen Takata, landscape architect, lead water resources planner and public involvement specialist with the U.S. Army Corps of Engineers Los Angeles District’s Planning Division, right, and her son, Seth, left,... More
Boy Scouts check out "Bobber the Safety Dog" materials
Boy Scouts check out "Bobber the Safety Dog" materials and other U.S. Army Corps of Engineers information during a May 12 community restoration-planting event in Norco, California. The event was hosted by the U... More
A Cub Scout and his leader prepare to plant native
A Cub Scout and his leader prepare to plant native vegetation near the Santa Ana River during a May 12 community-restoration planting event in Norco, California. The event was hosted by the U.S. Army Corps of E... More
Sheri Shiflett, biologist with the U.S. Army Corps
Sheri Shiflett, biologist with the U.S. Army Corps of Engineers Los Angeles District’s Environmental Resources Branch Planning Division, proves even biologists get their hands dirty during a May 12 community re... More
Brian Petree, deputy city manager for the City of Norco,
Brian Petree, deputy city manager for the City of Norco, California, displays a patch that was created to hand out to Boy Scouts and Cub Scouts during a community restoration-planting event May 12 in Norco, Cal... More
Seth Thomas, son of Eileen Takata, landscape architect,
Seth Thomas, son of Eileen Takata, landscape architect, lead water resources planner and public involvement specialist with the U.S. Army Corps of Engineers Los Angeles District’s Planning Division, gets assist... More
Seth Thomas, son of Eileen Takata, landscape architect,
Seth Thomas, son of Eileen Takata, landscape architect, lead water resources planner and public involvement specialist with the U.S. Army Corps of Engineers Los Angeles District’s Planning Division, puts the la... More
Workers put the finishing touches on the drip irrigation
Workers put the finishing touches on the drip irrigation system for the new vegetation planted by about 120 volunteers during a May 12 community restoration-planting event in Norco, California. The event was ho... More
Colored Postcard Railway Viaduct
1907 post card of the "Largest concrete viaduct in the world near Riverside, Cal., on the Salt Lake Route." Viaduct over the Santa Ana River in Riverside, California. Located on the Los Angeles and Salt Lake ... More
Arroyo chub (left) and Santa Ana sucker (right) in Santa Ana River (34...
Photo by Joanna Gilkeson/USFWS.
Arroyo chub in the Santa Ana River (35303592002)
Photo by Joanna Gilkeson/USFWS.
Arroyo chub swimming in the Santa Ana River (35303590282)
Photo by Joanna Gilkeson/USFWS.
Santa Ana River woolly star (5927478093)
Santa Ana River woolly star (Eriastrum densifolium ssp. sanctorum) is a shrub that can grow to about 3 feet in height. This plant is restricted to the Santa Ana River drainage in southern California. Photo Cre... More
Santa Ana Sucker (35430324446)
Santa Ana suckers are listed as threatened under the Endangered Species Act. There are three isolated populations left in southern California. This sucker is photographed in the Santa Ana River. Photo by Joann... More
SAR-Mentone2
The Santa Ana River downstream from Seven Oaks Dam, CA
Diseño Del Rancho Los Alamitos 1852 Los Cerritos Santa Gertrudis Coyot...
Diseño Del Rancho Los Alamitos 1852 Los Cerritos Santa Gertrudis Coyotes Siérritos Bolsas
Appendix to the Journals of the Senate and Assembly of the session of ...
Identifier: appendixtojourna19175cali (find matches) Title: Appendix to the Journals of the Senate and Assembly of the ... session of the Legislature of the State of California Year: 1853 (1850s) Authors: Ca... More
Oil and gas yielding formations of California (1900) (14579526340)
Identifier: califoilgasyield00wattrich (find matches) Title: Oil and gas yielding formations of California Year: 1900 (1900s) Authors: Watts, William Lord, b. 1850 Subjects: Natural gas Petroleum Publisher:... More
Santa Ana River Hydroelectric System, Abandoned Tunnel, Redlands, San ...
Survey number: HAER CA-130-R Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Abandoned Tunnel, Redlands, San ...
Survey number: HAER CA-130-R Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Abandoned Tunnel, Redlands, San ...
Survey number: HAER CA-130-R Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Abandoned Tunnel, Redlands, San ...
Survey number: HAER CA-130-R Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Abandoned Tunnel, Redlands, San ...
Survey number: HAER CA-130-R Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Abandoned Tunnel, Redlands, San ...
Survey number: HAER CA-130-R Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-3 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-V Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-3 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-V Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-3 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-V Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-3 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-V Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Revolving Fish Screen, Redlands,...
Picryl description: Public domain image of a hydroelectric dam, industrial facility, power generation, water cascade, free to use, no copyright restrictions.
Santa Ana River Hydroelectric System, Revolving Fish Screen, Redlands,...
Picryl description: Public domain image of a hydroelectric dam, industrial facility, power generation, water cascade, free to use, no copyright restrictions.
Santa Ana River Hydroelectric System, Revolving Fish Screen, Redlands,...
Picryl description: Public domain image of a hydroelectric dam, industrial facility, power generation, water cascade, free to use, no copyright restrictions.
Santa Ana River Hydroelectric System, Flume & Tunnel below Fish Screen...
Survey number: HAER CA-130-E Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Flume & Tunnel below Fish Screen...
Survey number: HAER CA-130-E Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Flume & Tunnel below Fish Screen...
Survey number: HAER CA-130-E Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-I Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-I Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-I Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-I Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-I Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Machine Shop, Redlands, Sa...
Survey number: HAER CA-130-L Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Machine Shop, Redlands, Sa...
Survey number: HAER CA-130-L Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Machine Shop, Redlands, Sa...
Survey number: HAER CA-130-L Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Machine Shop, Redlands, Sa...
Survey number: HAER CA-130-L Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Machine Shop, Redlands, Sa...
Survey number: HAER CA-130-L Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Machine Shop, Redlands, Sa...
Survey number: HAER CA-130-L Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-2 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-P Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-2 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-P Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-2 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-P Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-2 Forebay & Penstock, Redlan...
Survey number: HAER CA-130-P Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Flumes & Tunnels below Sandbox, ...
Survey number: HAER CA-130-G Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Flumes & Tunnels below Sandbox, ...
Survey number: HAER CA-130-G Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Flumes & Tunnels below Sandbox, ...
Survey number: HAER CA-130-G Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Flumes & Tunnels below Sandbox, ...
Survey number: HAER CA-130-G Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Flumes & Tunnels below Sandbox, ...
Survey number: HAER CA-130-G Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Flumes & Tunnels below Sandbox, ...
Survey number: HAER CA-130-G Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Flumes & Tunnels below Sandbox, ...
Survey number: HAER CA-130-G Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Flumes & Tunnels below Sandbox, ...
Survey number: HAER CA-130-G Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Flumes & Tunnels below Sandbox, ...
Survey number: HAER CA-130-G Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Flumes & Tunnels below Sandbox, ...
Survey number: HAER CA-130-G Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Transmission Lines, Redlands, Sa...
Survey number: HAER CA-130-X Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Transmission Lines, Redlands, Sa...
Survey number: HAER CA-130-X Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Transmission Lines, Redlands, Sa...
Survey number: HAER CA-130-X Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Transmission Lines, Redlands, Sa...
Survey number: HAER CA-130-X Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Transmission Lines, Redlands, Sa...
Survey number: HAER CA-130-X Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Transmission Lines, Redlands, Sa...
Survey number: HAER CA-130-X Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Prado Dam, Service Vehicle Garage, Santa Ana River near junction of St...
Significance: The construction of Prado Dam was a significant event in the history of flood control in southern California and specifically Orange County. The Dam has played a vital role in the economies and d... More
Prado Dam, Service Vehicle Garage, Santa Ana River near junction of St...
Significance: The construction of Prado Dam was a significant event in the history of flood control in southern California and specifically Orange County. The Dam has played a vital role in the economies and d... More
Santa Ana River Hydroelectric System, Santa Ana River Diversion Dam, R...
Survey number: HAER CA-130-A Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Santa Ana River Diversion Dam, R...
Survey number: HAER CA-130-A Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Santa Ana River Diversion Dam, R...
Survey number: HAER CA-130-A Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Santa Ana River Diversion Dam, R...
Survey number: HAER CA-130-A Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Santa Ana River Diversion Dam, R...
Survey number: HAER CA-130-A Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Bear Creek Diversion Dam & Confl...
Survey number: HAER CA-130-B Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Bear Creek Diversion Dam & Confl...
Survey number: HAER CA-130-B Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Bear Creek Diversion Dam & Confl...
Survey number: HAER CA-130-B Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, Bear Creek Diversion Dam & Confl...
Survey number: HAER CA-130-B Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work
Santa Ana River Hydroelectric System, SAR-1 Powerhouse, Redlands, San ...
Survey number: HAER CA-130-J Building/structure dates: 1898 Initial Construction Building/structure dates: 1905 Subsequent Work Building/structure dates: 1904 Subsequent Work